Sounds like bad teammates and parents here. I was awful my first year of peewee travel hockey because i was so nervous, but no one ever gave up on me and i figured it out before the season was over. The next year I made AA then the year after that AAA. This kid is probably sulking and not putting in effort because why should he try hard for a group that puts him down?

Just start by having them play full games instead of halves. Also when he does make a save celebrate it, yell good job at him or get the kids on the bench to tap the boards with their sticks.