In most of the families parents pay very less attention to stuttering until the encounter the real problems during the college life and in getting first job and following job. Your motivation is highly important and speech therapy is good ,he can talk better for few months then stutter will relapse. It's a life long prob but late teen years and till 30 are toughest years. Later it will reduce and your mind will get adapted to it and a no care attitude develops and they live happily in 2nd and 3rd part of life. Encourage and always have a smiling face with your son , stutterers have few bad days in a month , strong bonding and love from mother ,father and wife will reduce the effect alot.