best friend troubles

i don't feel like google will have a good answer so here this is... my best friend has mental illnesses and i know that and she struggles and she has this boyfriend that her parents absolutely will not let her date or talk to but she is still secretly doing this behind her parents backs, she is grounded from a phone and boyfriend for 2 years and she is starting to get on my nerves and it's hard for me to handle her its just that things annoy me and i have to be fragile with her and i'm her "person" besides her bf😒 but i can't do anything to hurt her but it's just that anytime she is staying a night with me i let her tlak to her bf on my phone and it's so annoying bc she just super glued to my phone and if i try to snatch it from her she gets a tight grip and i can't hit her bc she has abuse triggers from when she was little and i can't yell or get mad at her and shes smart enough to twist words so it's hard to just even talk things out without saying something wrong, i can ask for my phone but she'll say 1 sec or hold up her index finger which gets so annoying bc it's my phone and she's lucky i even let her talk to him, i give up so much for her to tlak to him because he makes her happy and i can't have her not happy with all the thoughts in her head bc idk what'll happen and her mother won't let her so i just feel obligated to...