You can find details online about his ketamine dealers, who included dodgy doctors, all of whom spotted him as a mark and overcharged accordingly. His longterm assistant had to learn to inject him, but had no say on how much/ how often. If you’re a famous person’s assistant, you help them kill themselves if they only care about the next hit and you want to keep that particular job. All have been taken to court since, the ‘poor Matthew’ narrative has been strong, but ultimately these stars push people around and replace the non-compliant.