The volume may be from him trying to get the word out. When the volume is high, does it seem like he's pushing/forcing through the word? That's very common for stutterers who block, sometimes they'll have some sort of tick or breathing issue when trying to force words out. If he somehow could WANT to get help or be bribed (video games/money/whatever) to practice techniques, I would suggest you pursue that option immediately. Be careful of the medical community suggestions and ALWAYS get referrals from other stutterers. Call them and talk to them. IMO, the best coaches are those who **used to** stutter. 1. They know stuttering & 2. They beat it. His dad **should** be concerned for bullies and future employment. It will 100% affect his entire life if it continues. However, your son will have to want help for it to work. And one day, he may want to get real help. I didn't practice self help till my late twenties. Mostly because most of the medical suggestions were weird and didn't work. Now I've found several resources and I've created tactics for helping make it unnoticeable.