My parents are divorced and my younger brother (who is 14) lives with my Dad. He told me that he is having problems living with my Dad and wants me to adopt him. My Dad is very hard to live with and I believe he is bipolar. My brother cries to me because he doesn't want to live with him. Can my husband and I adopt my brother?

You can adopt a sibling but both your parents will need to waive their rights. https://www.askmehelpdesk.com/adoption/can-husband-adopt-brother-386823.html When they divorced how was custody laid out in the decree?

Your dad (and mother) would have to be willing to allow you to adopt him. There is no way you can adopt someone out from under a parents nose.

Can you prove he is abusive or negligent under the legal definitions of a court?

The more I think about this most 14 year old I know would fit this picture. I see no abuse and what do your mom and dad say about this?