Honestly, I would let her go. If your gut is telling you it's not going to work out, let her go. The second family is more beneficial to you as a BUSINESS. I think if you feel the second family would be better suited, I would go with the other family. I think maybe mom is feeling a little guilty about leaving and you letting her go could be her go ahead to drop the job ad stay home - because that is clearly what she wants. Do what's best for YOU as a BUSINESS. Don't let your emotions get the best of you. I would return her deposit, just for good faith, and simply explain that her lack of consistancy clearly indicates that she's not ready to part with her son.