Hm, we have many amazing czech children books that are not translated or straight untranslatable, which is shame. Czechia has very neat, funny and lovely fairy tales (like robber Rumcajs or little Mole for smallest kids, those might be in your reach.) But if you want to please a boy around school age, I loved and my boys are now falling for "Nicolas' trouble" from Goscinny, illustrated by Sempé. I translated from czech, no idea how the book is called in english since it's several books and french. But it's hilarious, this book basically always ends in these little 2nd grade shits having a fistfight over some nonsense. Exactly like my sons.