Hi, I am Dr. Peter and would like to help.
1- Any diarrhea?
2- When was the last time this puppy ate?
3- Is he weak?
4- Can he walk?
5- When did this start?
1- Last night though she had diarrhea but did not have these symptoms?
2- How was the diarrhea, any blood or mucus (jelly like)?
3- Besides mom's milk what are you feeding them?
The symptoms this puppy is exhibiting is consistent with hypoglycemia (low blood sugar). You need to take some pancake syrup, nutrical or honey and rub it on his gums. This is where it get complicated, because he needs to eat but if vomiting then will vomit the food. You are right to believe the diarrhea could be from Giardia or Coccidia. I will recommend to take this pup to the vet so they can treat IV. If you do not have access to a vet, continue applying the syrup on his gums every half hour until he starts coming around. Then offer small amounts of rice and chicken and keep him on this diet; if does not eat, apply more syrup. Do not allow more then several hours to pass without some syrup or food.
Change the diet on all the pups and feed rice (75%) and chicken or ground hamburger (25%) until the diarrhea resolves. Speak to your vet about placing them on metronidazole and have a direct smear of their feces done.
If you have additional questions I will be glad to answer them.