Formal:
* Mon garçon fatigué: This is the most literal translation and is appropriate for formal situations.
* Mon fils fatigué: This is another formal option, emphasizing the boy's status as your son.
Informal:
* Mon petit garçon fatigué: This is a more affectionate way to say it, using the diminutive "petit" to show endearment.
* Mon chou fatigué: This is a very affectionate term of endearment, meaning "my darling."
* Mon petit bout fatigué: This is another very affectionate term, meaning "my little one."
Other options:
* Mon petit bonhomme fatigué: This is a playful term of endearment, meaning "my little man."
You can choose the best option based on your relationship with the boy and the situation.