You're getting great advice here!
Just wanted to add something as a point of clarification:
BPD = Borderline Personality Disorder
BD= Bipolar disorder
I can follow what you mean in this thread because the title says Bipolar, but had you just said BPD it would be confusing. You would get much different advice if you were diagnosed BPD rather than BD. It's much more common for people to write/type BPD for borderline, and just bipolar for bipolar disorder. I actually rarely see BD written, unless it's in support forums made specifically for that diagnosis (my brother is Bipolar I).
Also, the treatment you would receive as a pwBPD (person with BPD) would be vastly different than that of a pwBD. Mostly because BD is a mood disorder and BPD is a personality disorder. BD is manageable if you are strictly compliant with meds. Meds can help with the mood disorders that often accompany BPD, like depression and anxiety, but as it is an underlying personality issue, it requires much more intensive therapy to correct.
It's also possible for them to be comorbid - meaning you have BD and BPD at the same time - but it seems you are only mentioning being evaluated for BD, so it doesn't seem that your therapist has brought up BPD as a possibility.
Just thought you would want to know for the future. If you continue to create new posts and you were to write BPD when you meant BD, you would get MUCH different responses.
I don't have much to add because others have already said it - respect his boundaries. If he asks, tell him, without making it an excuse. But if he has asked for NC, respect that.
As far as advice re: a diagnosis goes, I know the idea of mood stabilizers is scary, but it could honestly work wonders. Granted my brother is type I, not II, so he didn't just have mood swings, he had a full blown manic episode that lasted 6 weeks and he had to be hospitalized. So of course I would love meds, they were the thing that brought him back to us.
He was really bummed about having to take meds at first, and had difficulty with compliance in the beginning because of some of the side affects. For example, he had tremors in his hands, and he is an artist, so that really messed with him.
But once they got the right combination of meds, he has been golden ever since. Also, he swears by a routine. He has to go to bed by a certain time, get a certain amount of sleep. He also works out every day. His psychiatrist said that he is his biggest success story for what regular exercise can do for someone with BD.
I hope you get some answers from your evaluation!