What is the ruling on a wife refusing to stay with her husband's family during Ramadan, alone with them and without her husband, given her husband's prior knowledge of her refusal to be away from him?

There is no blame upon the husband for traveling or being absent from his wife for a [valid] interest, as long as his absence does not exceed six months. If his absence exceeds six months due to an excuse, such as earning a living, then there is no blame upon him. He must provide an independent dwelling for his wife, and he is not allowed to compel her to live with his family.