sirius having a hard time with self-worth, which results in playing hard and fast with his own safety.
sirius picks fights, sometimes loses on purpose. needlessly endangers himself. sleeps too little. drinks too much.
sirius doing these things fully expecting his best friend to throw in the towel eventually because he’s not worth the trouble. hoping james will sooner rather than later so it hurts less.
outsiders looking in on their relationship wondering why james bothers when sirius is just going to keep screwing up.
james repeatedly proving sirius wrong. he worries. cleans him up. heals the scrapes and broken bones. tells sirius - sorry, but you’re stuck with me, no matter what you do.