Submarine Pitching Instruction in Bay Area?

My son (19) is finishing up is last year of American Legion baseball. He was preparing himself to finally hang 'em up until he filled in at pitcher last

At 5’8" 160# he did not have the velocity to pitch effectively until he began
throwing submarine-style.

H is now the teams closer and has pitched effectively in spot starts.

I have been trying to find instruction on submarine style pitching or even
a pitching coach in the Bay Area.

My son is now contemplating JC ball in Fall.