I haven't heard it, but I can't imagine it matters (except maybe I'll think he's maybe not so dumb as to think an NBA superstar would cut his career short in his prime to play out a lie about a serious illness). It is a highly insensitive, callous, discriminatory, stupid thing to say even in jest.
Fixed. Joke or not, it's incredibly stupid. Magic had a few good years left in the league. Why end it and face all the speculation and crap he had to endure because of it?