My father died 7 years ago and my brother 2 months ago. I am all my mother has. She expects me to be there for her emotional needs. She is 81, drinks heavily every night, and gets upset when I set boundaries. I live 4 hours away. I am emotionally drained and dread going to see her. She will not seek counseling and even canceled a meeting with her priest that I convinced her to make. Nothing I ever say is enough or right. I “don’t understand” is what I always hear. And “I would never talk to my mom that way” when I set boundaries or call her out on being out of line. Help
She should start with Office if Aging to see what is available. No, you can't help her emotionally.
You can work on not being emotionally drained yourself, but you can’t change her.
Boundaries for phone calls could involve frequency or content. If she has some old worn out complaints she has to trot out every single time (mine does!) you can choose to say "you already told me this please change the subject" and if she won't you can say "I'll talk to you later when you're ready to talk about something else" and hang up. Just an example.
I also submit that if she's had 80 plus years to form friendships and ties to a church or other community and yet has no one else but you that is her failure. She's had a literal lifetime to address her emotional needs and has chosen self pity and alcohol instead. You didn't cause that and you can't fix it.