Some snakes become irritable whilst in their shedding phase, so many people recommend not handling them for their own comfort and because if your snake does become irritable it is more likely to bite you (it's not exactly painful, but but it's a sign that he's mighty p****d off!).
If you handle your snake while it is shedding there is a possibility you will damage the new skin underneath or that you will stop your snake from shedding in once piece.
To be on the safe side, I would recommend:
1. leave him alone till he finishes shedding (I know it is tempting to get him out, but it's not for THAT long
)
2. keep the humidity levels high in his tank (by using a mister a couple of times per day.
3. Offer him food on his usual feeding schedule, but don't worry if he rejects it, this is not unommon for snakes in shed. If he does reject his food, throw it away (don't refreeze it) and offer him food again a few days later.
4. Make sure he has plenty of clean drinking water. Don't be alarmed if he submerges himself in his water bowl - he hasn't drowned, it's perfectly normal behaviour during shedding
Hope this helps