If he's happy in school and you can see a light at the end of the tunnel, I think it's fine.
But I would find a way for him to get challenged outside of his school environment. Sign him up for foreign language class, learn a musical instrument, take up a new sport, sign him up for online math curriculum. There are lots of ways to do it. Something that will force him to face a challenge on a regular basis. That should help make switching over to an environment where he's faced with challenge and actual work not quite such a shock!
