I don't know him and I'am not supporting him or anything but maybe he is actually saying the truth , I mean why would he give you 0.05BTC offer while he can simply pay you 0.005BTC on the first place ? It wouldn't make a lot of sense if you ask me (Ask him to give you the adresses the funds was taken from + a signed message from it ) .
Still users like him (who have knowledge on the hacking field etc ) shouldn't get hacked easily due to their knowledge of the security measures that should be taken so...