If her bitch was mated she can expect the pups around the 19th August - by that time she will notice the bitch has put on weight and will probably have let down her milk and try making a nest.
Tell her to get the bitch to the vet. They will be able to tell her if her dog is in whelp and advise on the extra nutrition and care the bitch will need - this is very important for the bitch's health as well as the pups.