(a) An order of disposition in a dependency proceeding shall continue in force until the purposes of the order have been accomplished.
(b) The court may terminate an order of disposition of a child adjudicated as a dependent child on or without an application of a party if it appears to the court that the purposes of the order have been accomplished.
(c) Unless a child remains in DFCS care or continues to receive services from DFCS, when a child adjudicated as a dependent child reaches 18 years of age, all orders affecting him or her then in force terminate and he or she shall be discharged from further obligation or control.