how old is the wiring in the house/area? If you can open the recptacle and see if there is a black/white/green wire in the box. if there is then there is a possiblilty that the circuit is grounded. Please let me know what you find. Becareful opening the plate.
you have to turn the power of and remove the recptacle and see if the cable is bx ,and properly fasten in the box,you realy need to test it from live wire to ground (box) to make sure its grounded,then just change the device ,your father has apoint there be carefull,
One way to achieve this is to have a GFI outlet installed.The ground on the GFI oulet can be grounded to the metal outlet box , providing BX armor cable or metal conduit feeds the box.Other wise simply using a three prong adapter will work if the ground lead can be attached to a section of the outlet box that is gounded. It is best to call an electrician if no one in your household is familiar with working with electricity.