One thing you need to realize about stuttering is that it's a neurological disorder with no cure at this time; there's not even any medications that have shown promising difference from control groups when the trials last for several months. People will make judgments about your son because of his stutter, and the burden will be on him to prove their judgments wrong. It really, really sucks, but we can't do anything else about it. As for speech therapy, the goal for most adult therapeutic interventions is not normal fluency, but rather a state in which stuttering occurs with less tension or a speech pattern that is volitional and consciously controlled due to relearning the components of fluent speech.