A man teaches his family that they should believe only in the Qur'aan, not in any Hadith.

Answer

This person who rejects all Ahaadith is a murtadd. It is not permissible for the family to even live with him. The nikah has ended. His wife is no longer his wife. If Allah Ta'ala does not guide him, nothing will convince him of the satanism which has become his belief. By rejecting all Ahaadith, he has rejected almost the entire Shariah. Thus, he is no longer a Muslim. The family must ostracize him. His wife and children should sever all ties with him as long as he persists with his kufr. The woman lives in the state of adultery with this shaitaan.