I am not deciding shit for anyone. I’m concluding your kid is most likely MtF, based on the info you provided — “in my simple brain he has a dick he’s a boy” + usage of the word “trans”.

And, even in the chance my conclusion is incorrect (the kid is actually genderfluid, or non-binary, et cetera), my point still stands, even if you pretend it doesn’t dammit. You highlighted you use “he/him” because the kid has a dick, regardless of the kid’s identity, that’s an arsehole move, doubly so coming from a parent. The right approach would be to use the ones the kid chose.

You’re the one assuming shit here

Not really.