I don't think he will be ruined. He seems to have a good head on his shoulders and can find confidence. Confidence is the only thing he is missing with his game. He's got the power to use all fields but once he confidence went he quit going up the middle and to right, just tried pulling everything which IMO led to alot more strikeouts than he has shown throughout his life in baseball.
I hear what you are saying, but confidence is one of the hardest things to fix. You can fix a guys hands, or a loop in his swing, but confidence comes from within and some never recover from that loss. Here is hoping he is different.