Snakes feel vulnerable leading up to shedding and are especially shy. A lot of snakes aren't interested in eating during that time. Some people feed their snake on schedule whether they're shedding or not. But, it's possible the snake may regurgitate. Like Alicia said, best to just wait until they're done shedding. Snakes' systems are built to be 'empty' for a while between meals. He'll be fine.