Legal Question in Family Law in California

Yes. And if he is dating he can hire a baby sitter just like anyone else too. Unless your custody agreement/order provides that you get some version of a right of first refusal to provide child care when he needs it, he is entitled to obtain any reasonable child care he needs when he is temporarily unavailable on his custodial time. Technically, you could insist that the family member meet you at his house, but trust me, you don't want to be the one in front of a judge on that issue or to refuse to abide by the custodial time order, unless he's asking you to drive an extra 50 miles or some other unreasonable thing.