This is some complicated stuff and you should really consult with a local attorney that deals with minor's issues--like juvenile dependency matters.Whether or not you have a shot at terminating the current guardianship depends on whether or not this is a Welfare and Institutions Code Juvenile Depenency case or--- of this is a probate guardianship.  If the court has jurisdiction of the child under Welfare and Institutions code 300 (because of abuse or negect), then you have a shot at ending the guardianship  by filing what is commonly known as a "388 petition."In probate guardianships there is a procedure to terminate the guardianship but under probate code 1601, only the "guardian, a parent, the ward" or an American Indian's tribe have the right to file such a petition.  So, as the Aunt/Uncle of a ward you would have no right to file such a petition.Go talk to a local lawyer and discuss this in more detail because there might be something I am missing here. Best of luck.