In this subtitle the following words have the meanings indicated. “Lawful custodian” means a person who is authorized to have custody of and exercise control over a child who is under the age of 16 years. “Lawful custodian” includes a person who is authorized to have custody by an order of a court of competent jurisdiction in this State or any other state. “Relative” means: a parent; a grandparent or other ancestor; a brother; a sister; an aunt; an uncle; or an individual who was a lawful custodian before the commission of an act that violates § 9-304 or § 9-305 of this subtitle.