Not saying that I sit there and scream instructions at my kid like you imagine.
But, I am saying that there can be limited, opportune moments when a player can get a small piece of information in a live game situation and then get an immense benefit by applying it in that situation. Game tape is one thing, but players learn a ton from trying new things in games and they don't always remember the game tape from two weeks ago.
A good coach will do that. I've not seen that coach often. If your kid isn't getting it at all from the coach, ever, absolute silence isn't the answer. I'd advocate giving your kid that little bit of key information just before going back to coach at half time, if convenient.
Example could be if he plays centerback and is holding a high line flat-footed when the other centerback steps up to make a tackle. At half time whistle-blow I wouldn't be against saying, quietly and privately, hey, when your other centerback steps up to make tackles, you have to be ready to drop and reform your line with the fullbacks in case the tackle is missed and the CAM makes a pass through that open space.
Crap coach will let 5 goals come through that way. 3 seconds with your kid in-game and they become better centerbacks for life.
Kids need to learn at their own pace. If your kid was in a play at school and they weren't hitting the notes right, would you say something mid play (even if quietly)? I've also found that when I'm watching the game in real time my observations aren't always 100% correct. That's where film comes in. I've had moments where I've gone "Oh, that's what they were seeing and that's why they did that". I totally get the frustration around coaches that aren't great (or just flat out bad). We've all experienced them. That's when I go to the DoC and give my feedback. That said, kids need to learn to listen to their coach (obviously, unless they harming them). The other thing I've seen is parents "quietly" coaching their kids on the sideline, yet 2-3 other players look over when it happens. It's just distracting for everyone. My recommendation is to reach out to the coach (at least 24 hours after a game) and share your observations.