“No help or involvement of any kind from someone whose son is on the team”
Quite honestly, it’s just a terrible rule. His coaching staff could use the help. We have a number of players in our boundaries with dads who could be tremendous assets (ex-college players, very good little league coaches, lots of free time).
I can see the problem of favoritism, but in these big team sports, I think it’s better to have all hands on deck and let the coach decide playing time.