Food for tooth problem?

One if my boys has recently dropped a bit of weight. I was watching him eat and noticed he tried to bite into larger things (sunflower seeds, peanuts) but can't. He just sorta chews on them without eating them, but he's been able to eat smaller foods and all that. I think he has something going on with one of his teeth (he won't let me check them though) and has a vet appointment tomorrow. He's still super active and playful though.

I was just wondering what the best food to give him for the next ~2 days are? Last night he was given his pellets soaked in a little water and mashed up and he LOVED it. I'm assuming things like banana are also okay?

Sorry if this is a stupid question, I'm a newer owner and have anxiety 😅