How did Hattrick afford his mansion on a Math teacher's salary?

Is selling answers to tests that lurative?

Is he and Dr. Watts working together to deliver those "packages" (that I suspect is illegal drugs)?

I am a Math teacher, an even though Math techers are in high demand, there is no way a Math teacher can afford that house.

So I think his parents must've been rich and gave him a small loan of a million dollars.