My mom has been dealing with various heart problems for about eight years. Two years ago she was also diagnosed as being in the early stages of Alzheimer's and Parkinson's.
Coping with a parent who has a disease (or several) is going to be different for everyone; depending on the situation.
The most important advice I can give you is for the family to be involved with her care. I go with my mom to all her doctor's visits and I am always armed with questions and reports on her. My mom's doctor is absolutely the best....she wants the family to be involved with the care, says it makes her job easier. Believe me, I have had doctors look at me like I had no right to ask questions
about my mom's care. But I feel that since I am the one taking care of her that I have the right to know what is going on and what I am going to be up against.
Another piece of good advice is to read up and study all you can on her condition. I have found so much information online that has helped me out so much. Support groups are also wonderful.
My husband and I live with my mom and I am her primary caregiver. I do all the housework, laundry, cooking, etc. Also, make sure Mom gets her medicines, help her with bathing, take her to doctor's appointments, or for bloodwork, among other things. She uses a walker to get around and is still pretty much in her right mind with the Alzheimer's. I think she does pretty good considering all that is wrong with her.
The best way I deal with it is just take it day by day. I know decisions will have to be made in the future about more advanced care, but as long as I can handle her at home, I will do it. I try to keep myself busy when she doesn't need me......I crochet, garden, read, etc.
Good luck to your mom and I hope things work out for you and your family.