If it is really dry, I agree softening it in a shower will help him pass it out. Sometimes it requires us helping them (though usually this is the last resort for me) and you always want to soften it before hand. After he passes it, make sure his next few stools look normal. Sometimes there will be some damage in his soft tissues depending on how easy it was to pass. Like small flecks of blood, usually it's nothing to worry about unless it's a lot, usually a little bit sorts itself out over a couple days of healing and some easier to eat feeders.