Hrmm.. as a new day of seeing this post again, re-thinking about it. I guess it depends on how sure you feel that your kid won't blow the opportunity when that big buck comes sauntering thru?
Cause I mean... re-thinking it today... I could totally understand that if some giant came along, and you've been putting in all this work into knowing that spot.... and... if it's like out here where just finding the bucks is a task onto itself... I could see a person, if they were concerned about making sure that harvest happens and is successful... making the executive decision have your kid step aside for a second on a more rare specimen coming out.
But, it sounds like in your area, that there is a more plentiful number of bucks (even multiple species!) to potentially pass-by. So in that scenario, I'm thinking you'd just suck it up and let him have the try, since it's not like it'll be decades before you see another larger one. At least, doesn't sound like that from your description, per se.