(a) If a durable power of attorney for health care entered into before October 1, 2013, was valid at the time of execution, it remains valid.
(b) A durable power of attorney for health care entered into on or after October 1, 2013, that evidences an intent that it is entered into under this subchapter is valid.
(c) A durable power of attorney for health care entered into on or after October 1, 2013, that does not evidence an intent that it is entered into under this subchapter may be given effect as an advance directive under this subchapter if it complies with this subchapter.