Once she has had the litter and you've gotten rid of the puppies, she needs to be spayed. This is only going to happen again, especially if she is not kept under supervision when outside. Tell your dad that. Repeat it: she will only continue getting pregnant if she is not spayed.

Any dog in heat, should not be outside unless supervised.

I get that you're a minor and not knowledgeable on the situation, but I would encourage you to do the research to understand heat cycles, the mating process, and canine pregnancy - since your dad is a dumbass.

Breeding her is called backyard breeding and is an unethical practice that results in many shelter dogs and dogs with behavioral issues. Owners shouldn't breed the dogs they purchase unless they go through their breeder to do so.

It doesn't sound like your dad is responsible enough to do that.