Is it full time? Like 8 hours a day? If yes then it is probably fluency shaping, maybe combined with other Methods and techniques e.g. correct breathing techniques. In my country Lots of speech therapists offer 4 weeks á 5 days a week (4-8hours per day) fluency shaping courses for 8-10k € and the insurance pays. The group of Kids and young adults learn together and are supposed to motivate each other to reach their aim. After the course their are their "newer" Version of themselves.