This is what you can do.
1. If you can afford the payment, you take over the payment and when you get your credit repaired your can have the lender put it in your name or better yet, just buy it from your brother, just be sure he's not "under water" with it.
2. Tell your brother to sell it. It is better to sell it than walk away and have a foreclosure on his credit for 3 years.
Call me and I'll help you. 770-912-5148, firstname.lastname@example.org, 30 years experience.