I’m not sure if my FIL is tired or in denial. Should we do more?

I think it's important to recognise that FIL is not alone in not appreciating how communication and comprehension skills decline in Alzheimer's disease, and that it will take him time and support to adjust to MIL's changing needs.

You see it all the time - families buy gadgets and gizmos and dot signs around the house "remember to take your meds!" "Sit down to pee!" thinking these will assist their loved one's memory, and then become frustrated when the meds pile up and there are still puddles all round the toilet.

I have just spent four mornings with a lovely lady who, sadly, is struggling with vascular dementia. Four mornings running she has been distressed because "I didn't know if you were coming" - it has been comparatively easy to reassure her and redirect her, but it's heartbreaking to think that every morning between seven and eight she is alone in the house and afraid that she will have to manage by herself. She is certainly not able to call our office number to check that we're on our way.

I asked her if she had a calendar (thinking I could display our call time on it), and she enthusiastically showed me the talking clock her daughter bought for her - you press a button, and it announces the day, date and time. Wonderful! But unprompted, it doesn't even occur to her to use it. Of course not. She has vascular dementia.

Then (different client) there is the door alarm which plays back a loved one's recorded message, e.g. "Mum, it's too late to go out now. Please get back into bed." I'm sure this is very reassuring for the lady when she approaches her front door at two in the morning. But at midday, when she's letting a worker in to help with her lunch call? - it's just baffling.

EVERYONE finds learning to negotiate dementia a challenge. Not just elderly husbands.

Ditto to what Alva stated. Also, you WILL be doing more, the question is: should you wait until there's some sort of trainwreck, or try to manage it before it comes completely off the rails?

We knew my step FIL had Parkinsons and was starting to have issues. He was in denial and was insistent that his wife was going to care for him and she "seemed" to be doing it except, upon a closer look, she wasn't. We soon realized she was having her own issues with short-term memory loss and cognitive decline, as well as physical decline. Her sons (my hubs included) seemed to be content to wait until (in my opinion) things descended into total chaos. Since we lived 6 miles from them I could see the writing on the wall. I worked full-time in our business, still had 2 kids in high school and a small grandson, helped my own elderly mom who lived next door to us, plus managed care for my mom's 2 older sisters out of state. I KNEW if no one started taking control and making critical decisions, it would become a sh!tshow that would land in our laps anyway. I worked (daily, almost another full-time job) for 1-1/2 yrs getting MIL to assign PoA (step FIL wouldn't do it), got them involved with social services and was talking to social workers almost daily, helped MIL apply for Medicaid (step FIL wouldn't do it), stopped them from driving, got MIL into a nice facility, helped the county get guardianship of my step FIL, liquidated their remaining possessions while their house went into foreclosure, and more. This is the short version of things and it may sound like a lot of effort and I'm not suggesting this is what it's going to be like for you BUT I can't even begin to imagine how much more work with much less desirable outcomes there would have been if we'd have hung back until the roof collapsed on us all.

My recommendation is to start doing more now because I don't think you'll regret it and it will be in the best interests of both of them. I hope you or someone has durable PoA for both of them. If not, this is the starting point. I wish you much wisdom and success in helping them.

I would say you are absolutely correct that he is in denial. If her care is really good he can continue to be in that state. But I think that you recognize, and your message to us indicates that you DO recognize, that this cannot long go on. You are on this. I trust you to know when you need to step in.

If she is at stage 3 and her husband does not have a good knowledge of the condition, I’d insist that he either be evaluated to see what’s wrong with him or he immediately read and view material that explains what he needs to know. If he’s arguing with her, he may not have the temperament to be a hands on caregiver for a PWD. I’d explore options for care to discuss with him. It can be stressful. He may not know how to ask for help.

Re Geaton's "sh!tshow that would land in our laps anyway".

A friend is living this right now. (FIL Parkinson's, cog decline, MIL afib, poor mobility). Both in/out hospital & unsafe discharges. Both lack of insight, judgement & planning. Have crossed that line from real thinking to magical thinking. *I WANT her to look after me - so it will be possible*

FIL stating his wife will do everything for him, including showering. One Doctor quipped "That wife who just left? Or do you have another one - a lot younger who is physically able to?"

Your FIL needs help.
He may not say this. He probably would deny it. He probably would refuse help.
I can tell you from first hand experience that it is not easy being a sole caregiver.
The first time I had a caregiver some in and I had time to do some things myself I thought I won the lottery. I got shopping done in half the time. But I did miss him by my side. I loved the quiet ride. But I did miss the noises he would make. (I know sounds odd but you get used to things like that.)
As long a MIL now understands some things it might be good to have someone come in so that she will be used to someone helping out.
Introduce a caregiver as a friend. Or say you are getting someone in to help with cleaning, the laundry, meals. Whatever works. You can start out with 1 day a week or 2 half days to ease into it. As she declines he will need the help for longer periods of time.
The time may shortly come when she should not be left alone for even a short period of time. You just never know what may happen.
Another option might be Adult Day Care if there is one open in your area. That can be a great help. My Husband was in one 3 days a week and it was great for both of us. (until I was asked not to bring him back because he kept trying to leave)
If you or your husband could come be with her for a few hours a day once or twice a week that might help him as well. And the longer you stay with her you can get a better idea as to how her decline is. (although a few hours does not give a true picture it can help)
A few suggestions for him.
*If he gets very frustrated with what she is doing or not doing, if it is safe leave the room. This will give both a chance to change the focus of what is going on.
*Redirect a behavior if possible. Give hands something to do. Fold towels, color , get a magazine and ask her to cut out recipes, clean out the "junk drawer" in the kitchen (everyone has one!)
* LAUGH. When you want to yell, laugh instead. Totally catches them off guard and they end up forgetting what the focus was and they laugh. Easy to redirect then. (found this out by accident once when the situation was so ridiculous that I wanted to scream but I just burst out laughing, changed my Husbands manner)
*Learn to accept help. People WANT to help they just don't know what you need. so tell them. Have a list of things that you need from the store. When someone calls and wants to visit say "sure tomorrow at 11:30 would be great, you can join us for lunch and "Betty" is much better in the mornings, but would you mind stopping and getting a gallon of milk and a loaf of bread for me".

People want to help and by refusing the help that is offered you deny them the pleasure and satisfaction they get from helping. (does that make sense?)

"Try and talk sense to her???????" Your FIL is seriously lacking in understanding about dementia, or he is in serious denial. Another possibility is that he himself is not entirely well. In any case, and whatever the screnario, none of this is good. You and the rest of the family, whatever that consists of, now need to sit with your FIL and find out how much he understands. That will decide what the path forward might be.

3rd sentence in your post points to the problem your dad is having. I know with COVID, that everybody is trying to be careful. He needs more people interacting in their lives since the burden of caring for mom has become a little too much for him alone. Talk with him about allowing family, close friends, community of faith to "visit" and help in small ways: cleaning home, sitting with mom so he can get out a bit, delivering groceries, share a meal, play games.... With other "normal" people coming in more often, he may feel less burdened with a woman who lacks "sense."

I think you may have also pinpointed that MIL has Sundowner's Syndrome, Print out an article or 2 about it that includes suggestions for dealing with her increased anxiety/frustration, anger in the evenings. Next time he vents about this, talk about how this will not "get better" without changing something: either evening routine or MIL starting a new medication to help her relax more. Give him the articles to read and make a "date" to check back with him to see what he is doing differently and the results.

Please be aware that 75% of people 75 years old and older have some form of dementia. Monitor FIL for dementia symptoms as well as MIL.

Just a note on leaving her alone. Can she still use the phone? Would she know how to call for help or get out if there were a fire? If someone knocked at the door would she automatically let them in?

The time when someone with dementia shouldn't be left home alone comes on pretty fast in my experience. If you are dealing with a caregiver who is having trouble accepting the diagnosis, be extra careful on letting him be the only one deciding that is is safe to leave her alone in the house.

alz.org will have some good, clear, basic information leaflets which will help him to understand what is (or may be) happening. I should have a trawl through their website, especially the sections for family caregivers, and print off a few selected pages for him to read.

A person can understand quite a lot about the disease and yet not have taken to heart some of the key points. It's a horribly frustrating and frightening (and, yes, exhausting) stage of caregiving, but with your support your FIL will get through, and may be quicker to recognise when he needs more help with her care.