Exactly what I was going to say (about the wet wash cloth).
You'll also have to be sure to keep his bottom clean, at that age, they are very prone to getting their poo stuck to their bums, which can prevent other poo from coming out, and that can cause other problems. So, use a warm wash cloth and wipe his bottom after each time he has a bowel movement.
Also, based on the breeders reputation thus far, you'll probably need to be concerned about worms and other parasites. Ask your vet about a wormer. You can get non-prescription wormers, but I'd ask your vet for some, just to be sure.
Because of the potential for worms, make sure you keep the floor cleaned and any poo spots disinfected.
Puppies are supposed to get de-wormer weekly from 3 - 6 weeks while in the care of their breeder.