He didn’t buy the DC house. One of Hellary’s ex staff is letting him “rent” it. IOW, the DNC is letting him use it. The house has had multiple owners in recent years and the current ones had it on the market for a while. Guessing decent people with children don’t like the neighbors.
If he’s getting the house at below market rent—he can be TAXED on the difference. And he’s probably accepting a lot of gifts he doesn’t pay taxes on.