Hey,

You need to get your parents to hire a professional behaviorist to help you out. This is a serious issue, it's not something that you, your brother or your parents will be able to fix on your own.

Unfortunately this is what happens when people neglect to do the proper training with their dog and isolate them to the backyard or, in your case, basement. It's not your fault. I'm only 17 myself, parents can be stupid when it comes to dogs sometimes so I totally understand where you are coming from.

So talk to your parents about finding an all positive reinforcement behaviorist to come to your house and help you guys to eliminate this behavior. If your parents don't go for it, then I'd be willing to guide you through what to do to the best of my ability to help you and your dog. I was actually only 15 when I started to work with aggressions, so I think you'd be able to do it if you had some help