I know it's a little late now for you, but I started "training" my kids before the puppy came into our home. They were 9 & 4 at the time. I never leave them unsupervised, they are never allowed to pick them up. They are only allowed to hold the doggies if they are sitting on the floor. Let your child help do things with the dog, like food and water, giving a bath. Maybe your not giving him as much attention any more because of the puppy, so letting him help with the puppy might help with the jealousy?
Good luck!