I apologize, but I don't understand these statements.
I know this is a poker term, but not sure how it applies to pitching, sorry. It's not a term I've ever heard applied to baseball.
Does this mean he calls the glove and not the ball? Sounds like your catcher needs to learn how to catch the ball and control his glove movement to stick the pitches.
These seem to be important if I'm going to issue any advice.
Adjusting to each umpire's strike zone is a real thing to some extent. The only difference here is that it's not a strike zone that if often called both ways when one pitcher is high velocity. Boiled down--you only have to adjust to how the umpire is calling YOUR strike zone. Make those adjustments and you will be successful.
I do have some understanding about umpires who squeeze the kids who have above average velocity. A slow pitcher is given up to 6 inches of extra plate-- to each side! A fast pitcher needs to actually throw a strike to get the call. This is not unique to your geographic location. Another side effect of slow vs. fast is that hitters offer at pitches outside the strike zone much more often for slow pitchers because they feel they can hit the ball. These same hitters do not have the same confidence level when facing a fast pitcher.
Ultimately, this extra challenge will precipitate one of two outcomes. The pitcher will either improve his control, throw strikes, and survive; or he will not improve his control and pitching will eventually no longer be an option. Decide whether or not he wants to invest the effort necessary to continue to have success.
I can't often turn a slow pitcher into a fast pitcher. I can make him faster, but not necessarily "fast." I have much better results working with kids to greatly improve control. Keep dialing in your son's control. I made a recent posting about structured bullpens where I recommended tracking deviation from the intended target for each pitch, then comparing these deviations over time to track improvement in accuracy. I also highly recommend bullpens that have concentrations of one or two pitches to one location done in blocks of 10-20 identical pitches. This type of bullpen really helped me pinpoint my control.