What a loser. The whole book is about how Artie uses the death of his father as an excuse to abuse drugs and treat his friends and family poorly. He was given more chances than he deserves and proved to be a total let down. Don't give this worthless bum your money, he'll just spend it on heroin.
I agree he is a selfish liar who pulls a lot of stunts that could be avoided. If you have to, buy the book used then, the money isn't going to him in the same fashion. I don't believe he is 'worthless' however.