We kids want to support and help them both of our parents at this time, which is especially difficult of course for Mom. She seems jealous of the attention Dad gets and is not into cajoling him to do things or rewarding when he does. Mom took good care of the family growing up and now with Dad, but she is not a warm and fuzzy type and the two have never gotten along well. What could, or should we do?
This is hard, hard work. The other hard thing is not taking a loved one's difficult behavior personally. I need to remind myself constantly of how warm and accepting my wife was before her illness. At times, she functions as a 2-3 year old with a hearing deficit. I can't expect her to be the flexible, attentive person she once was. She can't follow directions that involve more than one step. Getting angry with her, would only increase her own huge level of frustration. Despite the difficulty, please don't withdraw. Your folks need all he help they can get. Spending time with them is more important than anything else. They both need some "time out" from one another.
Unfortunately what you can't humanly achieve is making dementia behaviours tolerable to someone with a short fuse and scant patience. I should know. I've learned, painfully, to put myself on the naughty step for time out when I feel I'm losing it with my mother but I still can't just "not mind" when she's being… barmy. I don't think you yourself will get very far counselling your mother to use that kind of technique to relieve her own stress, but can you perhaps think of someone she trusts who could guide her? Maybe someone who's part of her own healthcare team? It's really hard, I sympathise with both of them.