Violence towards children from ADD Wife

Hi - I'm new here, seeking advice and support on how to deal with violence from my Spouse who a social worker I spoke to thinks is likely ADD.

My wife goes back and forth from being a reasonable patient person to one who speaks in very mean tone and language to the children and at times will hit them.  

I reached my bottom a few days ago after she hit our 7 year old daughter on the back.  I'm against any hitting and in this case, it didn't seem to me that my daughter did anything wrong, just a misinterpretation from my wife.

That's when I called the social worker for advice.  I spoke to my wife and didn't mention ADD, but said she needed help.  She said she wasn't interested - but I think she'll come with me to the social worker within the structure of marriage advice.

I'm handing around the house during all the trigger times - the morning out to school push, lunch time feeding (my wife is obsessive about table manners and finishing the food), and bed time.  I pitch in or take over when I start to hear that tone in my wife's voice start to change . . . 

I do want to give up control here, and if it was only me, I'd be hands off, but I'm very concerned for the children.  

My questions:

1)  How do I protect the children from my ADD wife without controlling her?

2)  If she is yelling at them or hitting them, do I intervene?  (She hates it when I do that)

3) Her emotional affect seems kind of off to me.  Like she is not really there, like she is buried somewhere inside.  Is that typical of ADD?

Thank you