Can a biological father get full custody of his child if the mother goes to prison?

There is no one answer. Any custody decision will be based on the best interests of the minor child. Is there a spouse to the mother who is the legal father? Is there a paternity decision regarding the bio father? Is the child presently in DHS custody? Is there any form of legal guardianship in place? Is there any issue with the safety and well being of the child being placed with the bio father? Sit down with counsel of your choice.