I have seen this (in varying degrees), and feel your pain.
I am fortunate to be with a group of experienced scouters that have dealt with this. You really won't change anything unless it comes from the whole troop/ leadership.
A group of dads I work with agreed together that during campouts, we would avoid interaction with our own sons. I would help the patrol my son was NOT in, and another dad would help my son's patrol. If my son came to me for help with, say, putting up his tent, I would ONLY direct him to another scout (or adult if appropriate), I would NOT give him other help or advice.
Have you tried talking to the dad? uncomfortable, delicate situation... I know. I have done this before. I told the parent the boy was struggling. I related my struggles and temptations wanting my boy to be the best, have the most fun, etc. and how difficult it is to step back. I suggested, and we made a pact. At the first campout, anytime he saw something and wanted to call his son on it, he was to catch MY attention and let me do it... and vice versa. I think it helped him to see that we all notice things from our own son that catches our attention, but others see as normal. We also decided he would go on the next campout (and I would stay home) and I would take the following one with him staying home. In that way, I made it sound like _I_ needed _his_ help, rather than me attacking his behavior.
Last tip... look for warning signs. Learn to watch for him seeking his son, or the boy seeking his dad. Intercept them. Find out the problem and solve it before they connect, give them a job to do, whatever. It's a LOT of work.
Good Luck. You are on the right track.