How much does he weigh currently? What size prey are you feeding? Feeding too large prey also tends to put them on fasts.
No matter how long the fast, it really only becomes a problem if the snake has lost a significant amount of weight or is ill. I don't remember seeing anyone with feeding live and not switching back before, but I would think to just wait him out this time! Don't give in LOL. Start thinking that if the snake looks fine and of nice weight and nothing else is out of sorts, it's definitely fine.
Just thought I'd quote this, are you still moving him to a separate container to feed? If so, that may be at least part of the problem. They'll have a much better chance of eating anything if you feed them in their cage.