I really am sorry your having a rough time. I know I had 2 litter last year that almost made me quit. All the other stuff I could care less and will not comment on it anymore.
Some things to think about... You don't have to answer me.. up to you. I don't sleep much at night because of some problems I have so that is when I think and I have thought alot about this..
Has your mom been tested for herpes? Not somthing they often test for but is popping up more. What about Poymetra?
Did you use any Heartgaurd, deworming, fea medication during her pregency. Was her pregency normal? Did she eat good? What about the whelping? Did you have to pull any puppies out? How long was each in the birth canal?
What about cleaning supplies? Have you used anything different on your floors? I heard reported ontime those swiffer mop where causing alot of problems for dog. I don't know how true that is.
Pesticides.. Did you use any in the house or in the yard through her preganacy? Like somekind of flea and tick prevention. I know I use to use it until I started breeding.
Like I said I hope this pup makes it. If it does not I would have an autopsies done but I don't think thay will show enviromental things I mentioned before. Good luck.