Congratulations!!!
I wish I could say that may first hook looked something like this, I was about twenty years older and the hook was nothing to show!!!
Keep your son in the track, this is some awesome talent here... !!!
For holding the pliers is no other help as training, for the pressure you have to come up with, to hold the material, bend a c-clamp in a size it will fit and hold the ends of the pliers together. This way your son only has to hold the pliers and not squeezing them together, too.
Badger