Hi Sacrar, when did you predict that your mother would come back?
If I were to predict, then normally I would have chosen Wei or Chou day. Reason: 冲中逢合.
Secondarily, we can also choose Xu day, because Self line is entombed on this day. Note that this second technique occurs rarely in the divination of "missing person"
To answer your question, Zi is not entombed in Chen in this hexagram