A band in the 1980’s struggles to keep their friendship intact and meet the demands of the job as their bassist slowly succumbs to addiction, they must find a way to help their friend or risk losing him and their careers.

The first thing is it’s a run-on sentence. The comma after addiction should be a period or it should be reworked. I think it sounds like a good story, though.

Also, it’s not clear who the main character is. Even if it’s an ensemble, there is always a main character who the audience experiences the story with, usually the one who has the most change to undergo and/or the one who drives the action the most. In “That thing you do” it’s the drummer even though everyone has an arc. So I would worry seeing this logline that the script may not feature a good solid main character with a clear goal.

And even if they can’t save their friend from addiction, can’t they just get another bassist? That points to the stakes. The risk of losing their friend to addiction is I think more compelling than the risk to their band or career.