When I was working for the foster care system in my state, the most I saw someone tested was 3x a week. This is in a red state, where drug use is highly frowned upon. For a blue state to be stricter on that than a red, I find that hard to believe.
That said. Maybe there is a stipulation that he has to pass a piss test to see the kids? That doesn't seem too far fetched to me. Plus, do we know the living arrangements for the kids as a fact? Like, if he can only see them for a day, or certain kids on certain days, and then has to return them to Grandma and Grandpa Rackets, I could see him going in every day to test so that he can pretend he is a good dad who wants to see his kids. Just speculating here.