How to sooth my son with HFMD? He can't take any solids anymore. Sometimes drinking water is also a problem.

perhaps his throat and mouth really hurts. I would up his milk intake, but still keep trying to feed solids like yogurt and ice cream. I wouldn't worry too much because it's likely only to be for a few days. Once he gets better, he is likely to eat more to make up for it! that's what happened with my son..