If you like Three Tales of My Father's Dragon...
Thank you for requesting a Book Match. I have not read Three Tales of My Father's Dragon, but here are some titles that combine dragons and/or exciting adventures for you to share with him:
The Dragon of Doom by Bruce Coville. Life in the village of Pigbone is boring until an aspiring magician and his talking toad come to town and ask Edward to help them slay the Dragon of Doom.
Farmer Giles of Ham: The Rise And Wonderful Adventures Of Farmer Giles, Lord of Tame, Count of Worminghall, and King of the Little Kingdom by J.R.R. Tolkien. Farmer Giles, his mare, and his talking dog go into the valley of the Thames to fight the dragon Chrysophylax.
The Chronicles of Narnia by C.S. Lewis. A classic series of fantasy books about the land beyond the wardrobe. Four brothers and sisters enter a fantasy land where they help Aslan, the lion, triumph in battle with the White Witch.