Sarah had taken quite a long time to recover.  But then she saw how well her son was doing ...without her. She decided to change her name to Rebekkah, and live in close proximity ...to watch her son grow up, from a close, safe distance.  She does not reveal who she is, and because she is believed to be dead, the ever expanding Tressel estate is in Stephen's name ...to be turned over to him in regulated stages, unbeknownst to him the name of the person who is managing it.  After all, Stephen is not that interested in building a financial kingdom for himself ...he is concerned with the furthering of God's Kingdom.