It's his own fault the only thing that's really wrong with his game is his first and second serve they are absolutely terrible and that's why he can't get by the second rounds nine out of ten times
I don't think it's all that much to do with his serve, which I don't think is absolutely terrible anyway, although admittedly it's never been the strongest part of his game, but more to with the lack of belief that he can actually progress far in tournaments - and he definitely looked like that in his match against RBA (who incidentally came very close to losing to Wawrinka in the next round). To me it stands to reason that if you consistently go out in the first two rounds of tournaments, and that often against players you should really beat, then it's bound to have a negative psychological effect. Probably a bit late now, but if he really wants to go on playing as he says he does, then seeing a sports psychologist might help.