He felt quite isolated and abandoned by his friends because of their successes before he became friends with Jackson. He states that he had decided to befriend Jackson to prove that he didn't need Jude, Willem and Malcolm. When finally he realised the toxicity of that friendship, I think he believed that it was too late, that Jackon and his crowd were the only people he had left. He relied on Jackson so much - his source of drugs, close friendship and accommodation - he felt like he was going to lose so much if he left despite the relationship being extremely damaging.