I am so sorry this happened. Zeus is an American Bulldog right? He is a bully breed, so Dog aggression is to be expected and not out of the ordinary and especially having another male dog. Dog aggression can come out of nowhere. I think your mom is upset and hopefully she won't rehome Zeus because of him being true to his breed, if you have to rehome him I would look for a very bully breed savvy home for him. I would crate and rotate for now, so you can keep Titan safe. Never ever leave them alone together unsupervised! I hope Titan will be ok. Dog fights suck and are scary.