Not that invested in Matthew Perry or his death, but I did read his memoir, didn't think it was very good
two things I can contribute:
ketamine is really addictive. one of my boys went on a Ketamine spiral and lost his mind. I had to talk him down, take his gun away from him. Dude was going to leave his house with a pistol in his waist for no reason. People were trying to kill him he said. He was sniffing like a gram or two a day, just fukking lost it. So, all the wellness ketamine bullshyt, is true, but it's still a drug.
Second: if you really wanted to be cynical, you could say this represents and extremely self serving and cynical person, and typical alcoholic/addict ---who went on and on about sobriety, wrote a memoir, and dude was spaced out on K the whole time.