The purpose of this site is to provide general information and NOT legal advice. Therefore, it is recommended that you contact an experienced family lawyer for legal advice. I do not practice in your state. My response is based solely on the law in my state Virginia, and how a hypothetical matter with these limited facts may be addressed in my home state. In Virginia, a peron under a legal disability (incarcerated) is entitled to the appointment of a Guardian ad Litem to protect his/her rights, provided that there is a matter pendinig in court. If the father's parental rights have not been terminated by a Court, he still has parental rights. Laws vary in each state, therefore, you need to speak with an experienced family lawyer in your jurisdiction to make sure that all relevant facts have been disclosed to obtain the best result. Best of luck~
This response is only intended for informational purposes and is not intended as legal advice or as a substitute for hiring an attorney in your state. Further, by sharing this information, it is in no way intended to establish an attorney client relationship with the reader.
Unless terminated by a court, your brother should still have his parental rights. It is likely that a court will be required to determine where the child should be placed going forward. You would need to work with the social services agency or whomever has current custody of the child to establish some visitation or seek further custodial rights. Also, depending on the type of accident that caused the mother's death, the child (or someone on the child's behalf) may be able to bring a wrongful death suit which could greatly benefit the child's life by providing funds for schooling and other activities. If this is a potential wrongful death matter, I would be happy to discuss the matter with you in a free phone consultation. Best wishes.