I have no experience with ferals, but from what I've read here over the years, I think giving them more time is the best thing to do. They've learned to trust you, but who knows how many other people they have come in contact with that they couldn't trust, so it will just take a little time before they know they're safe again. I think it's wonderful that your co-worker is willing to work with them, and it sounds like she's doing things right. She might want to force the one out just to make sure he's ok, but more than likely he is, and is just scared.

If you think it would make you feel better, you could go over and visit. This also might help them realize that they're safe - if you're in the room at the same time your friend is.

Patience and love is all they need and they'll come around. After all, look what it did for Magoo.