Angel, is it his fine baby hair? If so, a silk or satin pillow case or a square of silk or satin over hids head end of the bed will do the trick.

Can you have his hari trimmed? That'll encourage his "big boy hair" to grow, and in theory his grown up hair will not tangle as much.

Olivia has always had problems with her hair tangling....I now use a spray leave in conditioner before I brush it every morning to enable us to brush it without a tantrum/pain.

I use a VO5 adult one, but I am pretty sure you can now buy a kids detangler product from the supermarket....