Elderly father is abusive to elderly mother. What can be done to make him move to nursing home so his wife is not in danger?

Elderly father is verbally abusive and talks of physical abuse to his wife. She is at her wits end caring for him. He will not leave home, go to doc so no way to get any type of evaluation for him. He can not be left alone he is almost blind can not prepare food or drink for himself. He goes days that he will not eat. What can be done to make him move to nursing home so his wife is not in danger?