I can understand why she would want to re-rush, but why in the world would anyone want to forever be a new member?

Like Jocelyn said, once initiated into another NPC you can never join another NPC. When bids are distributed they are only good for one year, so it's impossible to "forever be a new member" (unless she rushes and receives a bid from the other 25 NPC sororities).

I'd advise your friend to look into the possibility of joining a local (if her campus has them), or a service or professional Greek organization.