I think the sponsored magic option is the best, for multiple reasons. First, you can make the book itself evil, and the jock have no power of his own. That way, your players can "save" the jock from the book and destroy it (which will for the moment be the same as killing the jock with power himself). However, the jock now knows some things about magic and magical power, and you can have him return as an emissary of something much nastier when nobody is expecting it (Think Cassius in DB). This will work very well if you have some sort of faith based character in your group, I think.
On the other hand, if you want him to have magical talent, give him a lore stunt on necromancy and let the book be his necromancy complexity focus. That way you would have Lore 1 + Stunt 2 + Focus 2 = 5 Complexity. If you need more, you can always give him more focus item slots. Of course you won't have it at the speed of evocation this way, and once he is defeated, he is gone.