pinkyphimu-
To answer your question based on what I have been on my campus: Panhellenic Councils on campus need to realize that the great way to help a struggling chapter is to punish the other chapters for rush infractions throughout the year. You cannot let chapters get away with promising girls bids, bringing the PNMs to their houses to party 1st semester, buying them drinks at the bar, oh geez...the list can go on. Name a gross infraction and name it here.
Of course, this is all theoretical. I have *never* seen this go on at my campus.
What does work? Supporting joint open rush parties for COB-ing, making sure that the struggling chapter is doing all they can do internally to stay open