Run, don't walk, away from the guy. He is clueless about pitching. He talks a good story, and it almost makes sense. My DD went to him for a while and he was worthless. My DD ended up being taught by Ed "The Snake" Serdar.
If you want a recommendation, try Val Wood (she is my daughter). She was an all-conference D1 pitcher at Ohio U. She works as a phys-ed teacher in Naperville. She has been teaching for a few years, and her young kids are doing fantastic in travel ball. She is at Centerfield Sports in Naperville.
Whether you use Val or not, find someone besides Bill to teach your daughter.