I think it's fine to let him use his hands at his age...at least he is showing interest in his food and in feeding himself which are the fundamentals you really want to encourage

Emily can use a fork but she will usually alternate between the fork and her hands for most of her meal, which is fine because she does get it all down eventually. She used to let us help her eat but in the last few weeks she point blank will not allow anyone to feed her so when we sit down to eat DH and I just let her go and try not to look LOL.

We stopped using those utensils designed for babies - the forks are blunted to the point of being useless and she used to just get frustrated she couldn't pick up her food and throw the fork on the floor. She has much more success with her "big girl fork" (our forks) - at least she has half a chance of picking something up so she will persevere with that. Perhaps you could try.