How do I get my father to agree to place Mom with Alzheimer’s in a nursing home?

This may come to guardianship of one of the siblings willing to take that on, and placement of both parents. Without a diagnosis that will be next to impossible. If he is the POA I would say the siblings need to get together and send a letter to the MD who likely cares for them both enumerating the concerns and the danger both may be in. While without a POA the MD will be unable to discuss with you, he may try to speak with Dad.
Other than that you are looking at guardianship and unless Dad is QUITE demented, you will not win in court; the courts are very loathe to take private citizen's rights from them and give them to the children.
Speak with Dad. Don't enable Dad by doing it all, and consider the siblings meeting and discussing next steps. If you cannot agree on this, then I would keep an eye peeled best I could and on you go. Not everything can be fixed. Not everything has a good answer.

The answer to your question about state guardianship very much depends on your location. Have you consulted an eldercare attorney on mom's behalf?

Have you considered seeking guardianship of her?

What is your dad's perception of a nursing home? Many elderly today still use that term, not realizing that care facilities aren't what they used to be years ago. We're not talking 1940's here. For one who doesn't know the difference, “nursing home” can be a generic term for an assisted living, memory care, or skilled nursing facility.
They're all different. They all provide different levels of care. A person has to visit these places to see what they are and what they provide. Your mom is certainly a candidate for MC.

I, too, was conflicted with having to place my wife in a MC facility. Was I reneging on my vows? Was I abandoning her? I decided that if I could find her a facility where she would be safe, have her meds managed properly, and where the staff knew her disease better than I did, that, indeed, I was caring for her.

In light of your dad's condition, he needs more convincing before he relents. Has her doctor suggested placing her? You could call your local Area Agency on Aging to have a social worker come over to evaluate her mental and physical abilities. They can suggest options for her, which at this point only one seems appropriate. Marriage vows do not require someone to care for their LO at their own home or at the expense of their own health. What would happen to her if he became sick and couldn't care for her. The time is now to insure her proper care.

"Placement comes first": have you identified the nursing home you'd like your mother to be admitted to?

It's easier to reject a theoretical plan than one that is fully worked out and ready for action.

How many of you are there propping them up? Are you all agreed that it's time to move your mother?

Options:

- try to get him to an elder law/estate planning attorney to explain how to manage his funds so that they both have an equal amount and that Medicaid is not the end of the world but he needs to manage his finances properly so she can qualify.

- explain to your father that her doctor says she needs a higher level of care. If he doesn't provide this you will report him to APS and that as her PoA he is not acting in her best interests. They will act to protect her, which may mean removing her from the home and him losing his PoA authority. The county then gets guardianship and they will have a say in the finances.

- explain to him that his children will go to court to pursue guardianship since he is not carry out his PoA (and this is provable). Then he will have no power.

- you could do your own family intervention and on a pretense remove her from the home (taking her for a girl's day out, shopping, whatever) and while one is distracting your father, another is packing her a things: clothes, medications, necessities, and she is discretely taken to another's home where she will stay until he acquiesces.

I wish you much success in getting your mom the care she needs and deserves.

This post is the reason why in later years people should not have their spouse as their PoA (or only PoA, if at all possible).

Thanks for your reply. He’s selfish and wants to reserve any funds for himself when he needs care. He also thinks this is what he signed up for( sickness and in health) but he isn’t caring for her in a safe way and doesn’t really want to care for her. We currently have someone coming in that helps 3 days a week. It was a struggle to get him to agree to that. But Mom had a set back and her mobility has been impacted, so she needs more help as my father can’t help her due to his physical and cognitive issues. Mom is in the advanced stages of Alzheimer’s, so she needs help with everything.

There may be many reasons why he won't. What does he say?

He just doesn't want to?
He will miss her.
Money.
He promised in *sickness & in health*

What reasons are on the other side?

24/7 supervision is required?
Safety issues? Wandering, refusing hygiene? Other behaviours that are hard to manage?

Is getting home help - or more home help an option?
Could Dad manage, afford, work with a team of Aides?

If not.. well... The only thing standing between the current situation turning into a crises is what? Luck & family support?

Now if family support reduced or stopped - what would happen?