I'm no breeder but I can give you some suggestion that I have seen here on YT...Try goats milk...its as close to moms milk as you can get..better than the puppy milk you get from the vet...one part goats milk and one part distilled water...give at room temp...you can get both in Walmart....make sure the pups are warm very important before feeding...if you don't have one already get a heating pad put in the whelping box under a blanket to keep pups warm at all times...I know Mom can't nurse, try putting a onize on her to keep the pups from nursing and let mom still clean and potty them...here is a another to try if the pups are weak....hope this helps..good luck.
Fading Puppy or Weak Puppy: Beef Liver Remedy