It is irrelevant that you have guests coming who are afraid of dogs. It is irrelevant that the puppies will be overwhelmed. It is irrelevant that a child might get bit or scratched.
It is only relevant that you told him not to bring his dogs. If you have any further contact with him before the party tell him it is your house, your rules. If he cannot or will not leave his new puppies at home, then he is no longer invited for this event. If he simply shows up with dogs, tell him he knew your rule ahead of time and he is not welcome.
His disrespect for you and your husband is astounding. Take the high road and be civil but don't tolerate this rudeness on his part.