Look...I'm going to be honest about this. This thread seems to be turning into a FIGJAM, both for you, as well as the youth.
Bottom line, it appears that you have NOT talked to the coach, and based on your replies you have not. In addition, your constant need to insult the coach, based on appearance or otherwise, seems to lend itself to an "agenda," of sorts.
Look, some coaches, especially school bowling coaches, are only there to fill time. Perhaps that is what is happening here, but you have offered little (if anything) in support of your position. You have heard this story ONLY from the youth and his parent (I've never seem a parent take something a coach said personally and then hold a grudge, have you?). Second, you have bashed his appearance, the school, and the quality of the team's bowlers. None of this lends itself toward a persuasive argument on your part.
If you REALLY have such a problem with the coach there is a solution. Document all of his ineptitude and contact the school. Present the athletic department with the evidence and then offer YOUR expertise to the school as the new coach.
Lastly, any parent who is serious about getting their youth training, in any sport, should contact a certified coach in that particular sport. Expecting any school coach to turn things around is laughable. With few exceptions, usually in the BIG sports (football, basketball, baseball), the coaches know the sports but not necessarily the techniques for improvement.
You want your kid in bowling, find a USBC certified coach. If golf is his/her game, then sign them up with First Tee. For other sports, find certified instructional leagues or camps. But to expect a school coach to work wonders, when most have other full-time jobs and are coaching to help out...that is simply misguided.