How do I get certain family members to accept my father’s’ diagnosis & help in supporting our mother’s care of him?

Perhaps the best thing to do is to separate accepting the diagnosis from providing whatever help is needed. If you and your mother get the help you need, it doesn’t really matter what is going on in your brother’s heads. Tell us what help you need, and let us brain storm with you about how to get it.

My suggestion is to take Mom away for a weekend and let ur brothers care for Dad. They will then see what Mom has to do with no help from them.

Sounds like you have a lot of experience work/education in mental health. Your siblings chose other occupations and have no true idea of the nature of this terrible affliction. Many people don't understand any more than trying to teach you how to work on computer boards, building a house or taking a car apart and rebuilding it. Alzheimer's (as with other mental health diseases) is too complicated and they are unable to grasp the concept of the brain "short wiring". When your Dad runs them off because he has no idea who they are then you can sit back, keep quiet and let reality hit them. You tried to tell them and the time for learning is too late.
Good luck Debra, thank God he has you!

My experience with men has shown me that they are not very proactive when it comes to family, they prefer to stick their heads in the sand and play "Let's Pretend". My husband was that way, my father was that way and my brother is that way...not to mention a bunch of others.

In addition, the wife normally just lets it roll, after all they are boys, most all caretaking falls on the women.

This disease shows no mercy, eventually they will have no choice they will be forced into opening their eyes, then they will tell you how to handle the situation.

Be prepared the day will come!

Siblings in denial is a common thread here, although I didn’t have to deal with it personally. At this point I’m not sure what kind of “support” you’re requesting of them...more help around the house? Help with shopping or to doctor appointment? Help to take car keys away if he’s still driving? Help looking for placement? Something else? Perhaps they think you’re overreacting, but if Mom makes the ask, they might take it more seriously. So my suggestion is to have your Mother call and ask them for the help. When she says “Your Dad’s doing X, and I can’t deal with it anymore, and need your help”, maybe they will give it more credence.

Sounds like they’re in denial, but Alzheimer’s marches forward and they won’t be able to deny it forever. As for educating themselves, you can’t force that either, they may have to learn along the way. Or they may distance themselves entirely, sadly, some people won’t deal with hard things

At some point, your brothers will no longer be able to ignore your father’s diagnoses. It’s very difficult for children to accept that their much-loved parent isn’t “perfect”. I’d bet they know what’s coming down the road for Dad, but they just need time to accept it. Don’t force the issue. The neurologist will still be there if they decide they want to meet. However, they absolutely need to support your mom. If things need to be done around the house and Dad can’t do them, they need to.