I can't speak for the law where you are, but if your daughter reported to her guidance counsellor every time she was being hit I suspect things would be acted upon,
but kids learn by example not word's.
Your daughter is basically being told that even if she is being abused their is nothing she can do about it.
Be careful you don't create a pattern for life. Making excuses for abusive partners is a hard habit to break.

Could you not put your daughter into self defense classes, or similar. So that she was at least in a position to defend herself.
I have o agree with a previous post, your making a rod for your own back by not making your wife answer for her behaviour.
Unfortunately at the expense of your child.

Words are not enough,it's actions that count.

Also is there anyone her who can shed more light on the assault or abuse laws in this gentleman state, that would be v.helpful.