Ok so yesterday we went to purchase a GSD, my son's dream pup. When we got there this pup looked pitiful... normally I would've walked away but something just wouldnt let me and neither would my son.. so we brought this pup home. It's not healthy. It was 6 weeks old and weighs 5 lbs. Its tiny. Our vet checked it this morning and agreed it was malnourished.. we arent giving up on it by any means... my son loves him. So HELP! How do I fatten up this pup and get it back to 100%? And no rude comments about getting it from a non registered breeder.. we just need help.