demand freedom for louis watson

My name is kimberly collins my issues is my brother louis edwarded watson jr. he has been in prison for 8 year now...i understand what he did was wrong i am nnot trying to deny that but i look up the law and the law say that the max for statutary rape is 5 year and my brother have got 20 year and i dont know why and that would not let her mother talk to the judge so she can help him out a little cause she know about the two ..i am trying to help him get out or reduce his sentence i need you all help....