Generally, I offer food every other week with snakes that are clearly fasting for winter, and at the height of the season I might just skip an entire month if the snakes are all breeding.

With yours, it may just be stressed from the treatments. If I were in your shoes, I'd keep offering food weekly for another month, and if he is still refusing each week, then skip to every other (or even every 3rd) until he does start eating.

-Jen