If you were in the US when your father passed away, yes it will remain valid. If not, you will have to request it to be reinstated which has a higher standard to be granted. If you are in the US and not in legal status, you will need another petition that was filed for you prior to April 30, 2001 (other conditions apply). You may want to consult with an immigration attorney.
Answered on Jul 29th, 2011 at 11:42 AM