Anyone heard of William.D Parry

Anyone heard of William.D Parry Hi everyone I was wondering if anyone ever heard of William Parry he is a licensed SLP his approach based on the Valsalva Hypothesis he also wrote a book : Understanding & Controlling Stuttering: A Comprehensive New Approach Based on the Valsalva Hypothesis I saw a video on YT of guy treated by him and he was doing very well he was so fluent.. I was thinking to take some sessions online with this therapist I don’t know if online therapy will work ? What do you think guys ?