Maybe offer a mouse instead of his usual rats?

With my ball python having been a pain to get to eat his whole life, I have learned some tricks that other people have found helpful.

What has worked for me:
Feeding in an all dark room, with the snake in a tub
Leaving rat with snake in a dark box for a while. *(only F/T rodents)*
Heating rat up as hot as I can without cooking rat or damaging snake

What hasn't worked for me:
Brain splitting
putting chicken broth in the water the rat's thawing out in to add scent


Since my guy is such a finicky eater, these tricks don't always get him to feed 100% of the time. Unless significant weight loss occurs until the point the snake becomes unhealthy, just experiment with new tricks to trigger feeding response.