With cloth diapers, they need to be stripped every now and then to remove build-up or they leak like that. I can't remember how it is done, but by googling the mom could find out how (I think you have to boil them or something). Also, some brands of cloth diapers are terrible and leak. I used cloth for my daughter and was given some Kushie brand ones and they were awful. I have had many dck's in cloth diapers and mostly had no problem. The other ones that leaked were the Sweet Peach ones from a diaper service. Ask the mom to either fix the ones she has or try a different brand.