The circumstances aren't clear. Does your daughter blame herself for your miscarriage at 7 weeks because of the wreck? If so, someone should tell her that miscarriages are unfortunately all too common and it had nothing to do with her circumstances. We've had two early miscarrages, two successful pregnancies, but the two that weren't born alive are in God's hands and we will see them one day.
Your daughter needs help, I'll pray for her and maybe she could return to you in NZ. God protect her and curse that demon of suicide off her.
I have an irritable uterus and was on bedrest for my whole pregnancy with my last child. Any activity or emotional stress (even if I didn't feel particularly stressed) started contractions. I explained that the pregnancy terminated probably a week earlier judging by HCG levels. I believe that she is harbouring a lot of guilt because of the correlation to my previous problems with an irritable uterus and blames herself regardless of reassurances.