Wife hits husband...

I need an opinion about this situation that is happening to someone close to me but they don't want any help.

Husband is very verbally abusive, so much that it causes the wife to snap and throw the first hit. Then husband out of "self defense" he hits back leaving marks. She only hits since it's out of frustration because the husband is so verbally abusive, then gets physical.

What is your opinion about this situation?