I'm a stutterer, and I have a 13 yo son who stutters. It affects every aspect of his life. I know exactly how you feel. I've gone through the same frustration with speech therapists. He's been treating off and on since he was five yo. It'll help to find a therapist who is a stutterer, or specialises in it because I think they have a lot of insight into the psychology of stuttering. As his mom your encouragement may fall on deaf ears. Our current therapist encourages finding something my son excels in to give him more confidence. It's a confidence issue at this point. IMHO. Getting built up by someone in addition to your love would be helpful.