I really have no recommendations on that. I can tell you what I use and it works just fine for me, and that is acidophilus from Walmart. It doesn't have to be refrigerated. Purists would probably be horrified, but it works for me. I sent some to my cousin who has two grandchildren with terrible constipation problems, and it helped them. I think she just opened a capsule and dumped some in something, don't know if it was food or drink, and don't think it would matter. You want to get to the right dose, so since acidophilus can also be used for constipation, and overdose will give diarrhea. So I suggest you have the mother go by the smell of the stool. Stool should have no smell, or very little smell, so when the diarrhea stops and the stool doesn't smell, she has gotten the right dose. I would start with half a capsule and up to one or two if necessary for one dose(meaning given in a small amount of water or food). Later on, for prevention, the mother can dump the contents of a capsule into a quart of milk or juice.

She is obviously trying to run out something, so Colloidal Silver would be good topically, but if she can't get that, frequent washing and complete drying. She should eliminate all sugars because sugars feed yeast.

But no matter if she cannot get an optimal diet, the acidophilus will help and will in no way hurt. If you have some acidophilus, or something similar, give ten of them or so in a plastic baggie for your friend to give to your friend to try...?