Almost 4 months since he ate. What to do?

[Daybreaker]

I'm not an expert but I think it's time to try putting in some live prey in the cage (try harmless pinkies as a start?), 4 months is just unhealthy!

Bolded: It's actually not unheard of for balls to go off feed for a couple/several months, especially when they get to the age when other matters (sex) are driving them. As long as the snake isn't losing dangerous amount of weight four months is nothing in terms of time IMO and not particularly unhealthy.