My Mom's (68) she's a very negative thinker and keeps on dominating me and my uncles daughter. Any advice?

Your problem is a very common one. This website is full of comments and stories of negative, unsupportive and selfish parents.

If a child continued to behave in such a way as to seek attention would you keep giving that child attention thus reinforcing the negative behavior? No. We'd leave that child alone and let them stew in their own juices. Don't give your mom the reward she's looking for which is attention.

However, you didn't say if your mom has dementia or not. That changes things. People with dementia have to dealt with differently. If she has dementia and is acting up to get attention try to redirect her, get her involved in something else. A tv show, a photo album, a simple chore that she can do. Something to distract her.

I know old family habits are hard to break but I'm assuming that you and your sister are adults. So if you want to go out, go out. You don't need mom's permission anymore. If mom doesn't like it when either of you go out that's her problem to deal with.

You're not going to be able to change your mom's behavior, you can only change your own behavior and how you deal with mom's behavior. If you give in to her, if you don't go out because she doesn't like it then you are giving her a payoff for her own bad behavior. Mom learns that all she has to do is throw a hissy fit and she gets what she wants. You have to set boundaries. Again, you can't stop your mom from behaving badly but you can change how it affects you.

Don't count on your mom to understand your feelings or to even want to understand you. Try to get rid of these expectations of your mom (that of a loving, understanding, caring woman) and see things as they really are. Create your boundaries, understand that there are behaviors you won't tolerate and then follow through. You and your sister aren't kids anymore and mom doesn't hold all the cards anymore. Be adults, take good care of your mom, and consider the source. She's mean and critical and a control freak. Why does someone like that have so much power over you?

This needs more details. I'm not clear if you can't leave her because she's ill or if you can't leave her because she's so demanding.

If it's because she's demanding, just do it, anyway. If it's because she'll ill, get an outside caretaker to help.