Just move on already. He only wants to play for Barcelona and will never initiate to leave the club by himself. The only thing that would make him leave is if Barcelona is forcing him out. But than you will end up with an unhappy underperforming...
Normally bad wingplayers you can transition to the back positions. So I would say, try him as leftback. But he cannot cross, so yeah he is kind of a hopeless case at this point.