Why not just tell him to get a new engine


Your problem is that the radiator is boiling over. Have your fluid changed and check for cracks in the radiator. A stipulation of radiator fluids ability to reach high temps without boiling is that it has to be under pressure. I had a crack in my radiator(nothing you would notice) that leaked out the pressure and caused the fluid to reach boiling point at regular atmosphere pressure. Boiling radiator fluid sounds like a freshly poured fizzy soda.

Good Luck