Priority Club (Holiday Inns) have a pretty nice promotion starting in May which would allow your father to reach Platinum level pretty quickly and rack up a lot of points for free nights. By Staying 15 nights (not necessarily in one stay), he would get 80,000 bonus points! That's enough for 8 free nights at a Holiday Inn Express or almost 3 free nights at most Intercontinentals!
The bonus therad in the Priority Club forum is here
http://www.flyertalk.com/forum/showthread.php?t=412211