Lip and the AA savior complex

Im a first time watcher and im currently near the end of season 9 and I absolutely cannot stand lip. I'm so confused about the way he acts towards fiona when she's going down a drunk spiral and with the whole kicking her out of the house for his sponsee breaking his sobriety. It doesnt make any logical sense, fiona is the one whose name the house is in, fiona gave up her whole childhood/life to raise her siblings and he acts like he has the authority to kick her out of the house and somehow no one else is intervening? Lip has such a savior complex after getting into AA and yet he doesnt even try to save or understand his sister the way he did with Youens or Brad, he dealt with them when they were actively relapsing and they pulled much worse shit than fiona did, somehow he gave them so much grace and not even the bare minimum to fiona. I dont understand why he hates her so much and why everyone in the family treats her like trash suddenly forgetting everything she's done for them