The type of training you need is formal obedience training. I would recommend sit means sit, so you both learn e-collar training. Unfortunately, it costs a small fortune and your brother is between jobs. Find something affordable with a professional obedience trainer.

Watch Donna Fenzi on YouTube.

Don?t use the crate as punishment.

To deter biting, you can pinch their cheek into their teeth. If he is mouthing your whole hand, stick a finger down his throat to gag him. They learn pretty quickly.

That dog needs exercise twice a day, up to an hour. Real exercise, not just a walk on a leash. Find something to mentally stimulate him so he gets worn down. Get him to run and stretch his legs, too.

Be consistent. Absolutely, unwaveringly consistent. Set a high bar for expectations and consistently enforce it. Dogs thrive on that structure. With time, that dog?s energy and persistence will be channeled into obedience.

Good for you for helping out your brother. If it wasn?t a family member, I?d flat out refuse to watch a neglected dog like that.