Hi Nic, it's not necessarily a problem, some dragons eyes look like that naturally. It's good that he's active + eating regularly. You can offer water with a syringe or spray bottle to hydrate him more if he will drink that way.
I agree, a lot of them tend to develop eye droops & usually it is nothing to worry about.
As suggested, just try to get more fluids into him, if possible to see if that helps out. His
eyes don't really look sunken to me though, he is a cutie there!