That's very harsh karma.
Nontheless, I hope he gets better. About the comments though, he didn't have to go so far. I've known for a long time that he can easily get annoyed and tend to be rude a lot as a response. Then again, if I had cancer and people were laughing at me and making rude comments about it, I'll be pissed off too. But I don't think I would feed the trolls like that.