what do i do if im attached to a hallucination?

hello. i'm not sure if i have schizophrenia or anything, working on that with my therapist and psychiatrist. just looking for advice from people with direct experience right now.

i experience mild hallucinations and delusions occasionally and one of the most common for me is believing i have an older sister. i told some of my friends i have a sister, just as a fact, and some of them got really upset at me when they found out it wasn't true. 

however, my sister is mostly just nice. she's basically my best friend. we hang out and gossip like middle school girls. i tell her about people who annoy me and she listens to me like no one i know does. i do have uncomfortable and scary hallucinations other than her, but she's my friend. 

i see people saying not to interact with hallucinations and not to encourage delusions and i don't wanna say that any of that stuff is actually good, but what do i do if im friends with a hallucination? i looked this up and really only found stories, not advice. i don't want to lose my closest friend, and i dont think there's a real chance of me getting antipsychotics anytime soon anyway for personal reasons. does anyone here have any advice or suggestions for what you're supposed to do if you're friends with a hallucination?