<Snipped quote by Mae>
Oh, okay, here's what I had in mind for the ability.
Since her max sanity is currently 14, if the sanity is over 50% (7), then for every 3 points of sanity she has over 7, allies gain 1 willpower. So if she had 13/14 sanity, it would be 13 - 7 = 6, 6/3 = 2, 2 bonus willpower. If it's under 7, then for every 3 points under 7, her allies lose 1 willpower, so if she has 4/14 sanity, she has 3 - 7 = -3, -3 / 3 = -1, -1 willpower for everyone.
So this early on, it's basically +1/+2 willpower for party.
I'll add the out of combat bit on, too.