Hi!

I have 2 baby kittens 5 months and Dalia is a nightmare for biting!
When she was littler it was ok as he teeth were just little but now flipping heck they arent so little!

Its just playing tho (although you should try while they are young to discourage it) my 2 kittens bite each other all the time. My big babies have never been biters.

Generally I just move my hand away from her and dont respond to her!
She doesnt bite for no reason normally when we are playing and she gets over excited!

So maybe just try ignoring him and slowly moving whatever he is biting away from him if you move it fast its like a game. Just distract him with a toy or something else.

Hope this helps! Its something to try at least!