Difficult dad. Any advice, how do you cope?

Kathy gave you some wonderful advice. Old rivalries between siblings have a way of returning during parent caring time. The only way to defuse this is to do as Kathy said. Don't take sides. Tell your brother that certain things are his responsibility and then don't do what was decided is his to do. Re-read Kathy's note and see if following her suggestions helps you.

In serious situations, family mediators can help, but try it on your own first. If you stay strong, tell them both that they must get along and tell your brother that he has just as much responsibility as you have, the situation may improve. I hope so, for everyone's sake.
Carol

You must have a talk with your Dad, and explain you can't do it all. That he needs his son. Split the chores 50- 50 with your brother. Explain to your brother you need a break. Men have their own way of settling their differences, don't get involved in fixing it. Don't pick sides. Tell each of them I love you both, and I won't pick sides. Fighting with the parent is an old sibling trick for avoiding helping. Make it clear that you won't pick up his slack. flatter both of them, on how strong, smart, funny, both of them are. Tell the other one how much the father loves the son, and the son the father.

Most importantly don't get caught up in the drama, and don't let your brother use this as an excuse not to help.

Boy, do I know this one! There is no sure cure for this type of thing. I do know that the people in your life can be retrained to deal with each other. Even grown ups revert back to bygone years in attitude and manners when family comes together. I have the ability to come in and leave after 2 days. My sister lives in the same town as mom and my brother lives with mom. I come from out of town on weekends so I can prepare. But, I prepare by memorizing 'facts' to share with them. I state facts as gentle reminders. "It's not mom, it dementia." and "Give her what she wants to eat in small amounts to make it easier for her to lift" and 'she only will drink 4 oz of water so only give her 4 oz of water at a time. A full glass is to heavy for her to lift." I use these statements when they ask why do you do it that way or why does she eat what you fix when we can't get her to eat at all. I also tell mom 'Jon is going to live with you and that is not going to change." as well as 'Kathy has your check book and is going to pay the bills and that is not going to change" I insure that my brother and sister hear me make those statements at least once a weekend so they know I support them in a firm matter. It is small things I do but I do them firmly. In this manner, I retrain my brother and sister to feed her smaller amounts of food, large plates overwhelm mom and she just decides not to eat. Or do give her smaller glasses of water more often so she drinks more water. I don't tell them how to do things, I tell them why I do things and those things more often than not work for mom. I also bought an ice cream maker, a small bowl one that works in 15 minutes and gave her 'ensure'. My brother can make ice cream, which is what she wants anyway. She gets at least some nutrition every day and that makes everyone feel better. She only eats about 6 ozs of it right now but it is better than the chicken in pancakes he was trying to make her eat! (I know, I said the same thing when he told me. He thought he was doing right by her, feeding her protein at every meal but honestly, chicken in the pancakes!!)
Men tend to think they can 'fix' everything. Gently remind your brother he can not fix old age but, he can help you and spend time with his father so when you lose dad, he won't be saying 'if only I had..."
Good luck

First you must know whenever you change family (or work) environments, there is going to be a period (3 - 5 yrs.) of adjustment. Your brother came in, and upset you and your father's routine, and of course there is arguing! The three of you need to sit down, discuss what and how you would like the family to function, what roles each will play and make up a chart if needed to assign different tasks for different parts of the house. That's how my family of origin (6)survived after the death of my father. Back then since there were 5 females, and one male, there was always "Queen (King) for the week" who did not have any chores. The chart was on the wall, everything was spelled out and there were hardly any arguments because everyone did what they were assigned to do. I hope this can help. I assigned this method to my CPS parents too.