Hi there! Out of curiosity, what has motivated you to ask for beak trims? Is there a case of scissorbeak preventing him from grinding his own beak down? If his beak is aligned correctly, regular destruction of toys should be enough to keep it from overgrowing to the extent that a vet would need to intervene. Even with scissorbeak, a vet might be able to carefully grind the beak back into alignment so that the bird can grind their own beak with toys moving forward. Either way, my point is that beak trims are by no means just a regular maintenance requirement of owning parrots, it's unusual you've had to do it multiple times.
If his beak is aligned OK then basically your biggest job is making sure he has destructible toys.
That said if he has alignment issues OR refuses to play with toys making trims necessary, you should really make sure that whatever vet you take him to doesn't clip/cut his beak, and instead it should be ground down with a dremel. If he's uninterested in food it's possible that they cracked the keratin in his beak in a way that's painful.
