Mom is getting more forgetful and confused about things which happened. I've been told not to "correct" but just go along. Advice?

You can correct, but just do it gently and know that in all likelihood it won't "register". So if your Mom says "Alva is coming to lunch tomorrow" you could say "I think I remember that Alva isn't with us anymore, Mom. She was ill a while back. Do you remember that". She either will or won't or will insist Alva IS coming to lunch. If the latter is the case then just ask what she would like to have for lunch. A gentle correction isn't a fight, and feel free to give it a try, and know that if you have to end with "Oh, I must be wrong, Mom" that will work just fine.

If it helps her understand something in the moment or keeps her from getting upset or hurt, you can try to help her realize the truth, but she might not remember what you told her for very long. The thinking gets stuck in a cycle and it doesn't matter how often you correct. Also, she might get angry if you disagree with her. Certainly, it doesn't help her to correct her constantly. Then she will be very confused. I try to follow my mom into her world. It gets pretty interesting in there and that is "engaging".

For years, my grandmother and I would talk about the horses in the field (we no longer had horses or a field), whether the children would sleep in the horse drawn wagon on our trip home over the mountain (I had driven my mini-van) and if I still rode Blackie (her horse for many years) to school each day. Clearly none of this made sense in our times but she was living in her times so I did too. We both enjoyed our time together. Just let it go and try to enjoy your mother's world.

No, do not offer a mild correction.

What you have to understand is that the person is right. What is going through your mother's brain, her version of events, is in fact what is going through her brain. Your problem is that it is different from reality.

The idea of engaging is to connect with your mother's version and then, through questioning and listening, figure out the route from her version back to the real one, if possible, and worthwhile, or to whatever keeps her safe and reassured at least.

You say this is about "things which happened." What sort of things?

While it’s not a bad idea to keep her brain active, you must realize her limitations and abilities. If you do some research on the symptoms of Alzheimer’s/ dementia, you will realize that trying to convince the person who suffers with it that there are no men hiding in her bedroom closet, that she just ate dinner five minutes ago, or that she was never a famous stage actress in New York City (some of my mom’s delusions) is fruitless. As her disease progresses, you will realize that even “mild correction” and “slight disagreements “ will just cause you stress and annoyance.

None of us wants to freely accept that our our loved ones are drifting away into a world of their own. That’s why this forum exists—to help us caregivers through it.

You need to understand that true dementia isn't something that will go away with "brain exercises", it is a group of conditions that result in progressive, permanent loss of brain cells. Trying to force someone with dementia to remember and engage in the "real world" is like trying to force an amputee to walk, there may be coping strategies that are helpful but you'll never recover what is lost.