It's going to be very hard for a huge enormous fat guy to manage a hamstring injury 10 years after he hurt it. He starts by losing 15 pounds so that he can get into efficient positions to deadlift and squat, then he deadlifts and squats. Massage/ART may be useful for the hamstring.
But he's not going to do any of this, because he's a big enormous fat guy. He lacks the discipline.