You can keep feeding him the way you are, if the mice are that small. You should look into getter larger prey items ASAP. He should be eating prey items as big around as the widest part of his body--not his head. The recommendation for a 5 day schedule is based on prey items that are appropriately sized. 5 to 7 days is fine for juveniles eating the right sized prey.
He's soaking in his water bowl because the cage is dangerously hot. The warmest part of the cage can be 90-95, but there must be a cooler area at 80F. Try cold water bottles if you cannot cool the air temperature any other way.