Sure, birds adapt remarkably well to disabilities. With or without beak regrowth, I'm sure he'll do just fine. I would imagine that pellets are less pleasant for him because it's more difficult for him to grind them with just one side of his lower mandible. Have you tried soaking them first? But also, you can give him an excellent diet without the use of pellets. I can't give my Ekkies any kind of pellet or they will wing flip and toe tap, so I make what I call a chop'n'freeze for all of my birds, and that is the majority of their diet. They only get Phoenix Foraging's UnPellet and occasionally some Goldenfeast South American Blend in their foraging toys, whereas the other birds get that plus Harrison's, TOPS, and an organic seed mix. Anyway, I showed my recipe for chop'n'freeze to two different avian vets, and both of them approved of it as a complete/majority diet for my birds. If you'd like, I can send you the recipe.