Personally, only the first 3 can be applied to me. I don't have "supporters," but I think these are good for people in general.
1 “I know exactly how you feel”
Better than telling me you know how I feel, you could always just empathize. Most of the time, I don't need or want a solution, I just need to know I'm heard.
2 “I am your friend”
It can be confusing for me when someone tells me they are my friend, and then when I struggle or they move away, they just aren't there anymore. I only have a limited amount of brain cells to devote to things. I don't want to waste them on people who will flake out. (I understand that people have their own issues. I'm not demanding 24/7 attention. I just like to know, if I put in time and energy, I'll get a little back. And I also know friendship is a two-way street, but sometimes I feel like I'm the only one ever making any sort of effort. And that's not okay, for "normal" people OR for brain-injured people.)
3 “Come on what’s my name, you should remember I have been with you a year now”
Like I just said, I only have a limited amount of brain cells. Sometimes I will not remember your name. Or your kid's name, or your job, or anything else I know you've told me before! It's NOT that I don't care about you. It's that after you told me, I learned something else that I needed those brain cells for. Sometimes I forget less important things, and sometimes I forget that I need to prioritize so I don't forget the important things. Quietly remind me, and please don't take it personally. I DO care about you, but sometimes my brain just can't handle everything.