Just want to say a few things that might not seem to belong on the mechanics and analysis forum. Take it for what it's worth from a guy who has been there.
There appears to be much better chance for success in tweaking mechanics if the pitcher himself is the one doing the evaluating. Fathers certainly have the interest but not as much skin in the game. I think this site has born that out. And I think 16 is not too young to be expecting him to mostly "take it from here".
A lot of spinning ones wheels can be avoided if you guys can do a few things. First and foremost: trust your gut instincts. Don't rely on an "expert" solution. Do your diligent research, trust intuition and do what is best for your specific situation even if it means conflicting with expert advice.
If something don't seem right, it isn't. By the time you wait for a trusted expert to tell you it's wrong, you are probably too late to change it.
Remember some professionals have an inadvertent conflict of interest. Some may be simply looking to profit and some looking for a name to attach to advertising. These are not wrong in and of themselves, just not what your goal is.
If you trust yourselves you may often be convinced that doing something very few people are doing is the right thing to do. In other words you may be thinking of going against conventional wisdom. Lots of good decisions have been made that way.
Sure, you are going to make some mistakes but if you trust yourself and act on those gut feelings, you won't suffer from inaction do to fear of failure or information overload.
Good Luck! The kid looks like a winner to me. Throw him out there and see if he floats.
Have of prosperous New Year.