I have referred people to the place you mentioned, but have also heard from mental health professionals here that that organization is rather useless because the authorities there are reluctant to get involved in "private family matters".

Perhaps a hotline would be better utilized by victims of abuse here because then they could call anonymously and get information before deciding to take the very public (and sometimes risky/dangerous) step of physically going to a building with that sign on it.
Alternately, if the situation was deemed enough of an emergency, the hotline could immediately call the police/hospital and dispatch them to the victim's location.

"If you're looking for sympathy, you'll find it between sh*t and syphilis in the dictionary."
- David Sedaris