He blames everybody else instead of admitting that this is a problem of his own making.
of (one's) own making
Owing to one's own actions, especially one's mistakes or poor decisions. I know you're angry that you won't be able to compete in the tournament, but this whole mess is of your own making!
of your own ˈmaking
(used about a problem or difficulty) caused by you rather than by somebody/something else: The problem is of your own making, so don’t try to blame anyone else.