Why would a half-dragon be able to handle a whole one? Will he still get level 2 spells, or does he need education for that? I don't remember that part, but if he does, then knowledge and spellcasting won't be wasted.
P.S. You don't need to know any schools or have any skills, including education, to cast level 1 and 2 spells.
Bow down and hear our cry,
Our earthly rulers falter,
Our people drift and die,
The walls of gold entomb us,
The swords of scorn divide,
Take not thy thunder from us,
Take away our pride.
G.K. Chesterton: English Hymnal