I got one yesterday from Heracles, the E-mail says it's good until 7/31/2010.
They have an expiration date that's not directly relative to the date of purchase/award. My guess without further data is they expire on the last day of the 2nd month after award date. Awards given 5/1-5/31 will expire on 7/31, 4/1-4/30 expire 6/30, etc. This is pure speculation, but it's safe to assume your friend's $ will no longer be valid on 8/1.