I know you must love him very much. being supportive does not mean an all-encompassing, unconditional support.
That is denying the reality before you...these situations and problems he is bringing into both of your lives.
(I have a severe form of bipolar also and I am still responsible for all that I do and say. It doesn't give me a free pass.)
Where is the "you" in all of this? It seems like you are subsumed into a service position to the bipoolar and alcoholism.
Having either or both of these doesn't make any wrongs right.
I don't like being lied to and if someone does that I am going to confront them.
If they are pulling crap that effects me I am going to speak up about that also.
it is my responsibility to manage my life.
and I don''tn want to give it to someone else. I may choose to share it....and that is a privilege to both them and myself.
but I have to have respect....mutual respect or I don't have anything.
I have spent 20 years learning how to stand up for myself.
It is one of the best gifts I have given myself and others.
It works.