bloody hell, ouch! Private hospitals here are amazing just like in BKK but also treat you like a cash cow especially if you have insurance. Assuming she'll be in a private hospital in Thailand to give birth then it makes no sense to me unless it happens to be considerably cheaper in Thailand compared to the private ones here.
no noticeable differences between the private hospitals from my experience, certainly not Samitivej in BKK and FV in HCMC anyway. Not that I have experience of giving birth in either...