From personal experience, CX will open up more seats at least within 72-48 hours prior to departure.

You have Silver status, so that's good. You also have a higher booking class than others who might be waitlisted in S, V, L class.

Chances are that CX will most likely confirm you.. and given that the flight is overbooked.. you might be slated for an op-up... BUT only if you're confirmed.

Tell CX res (not MPC).. that you NEED To travel on that date because of a family emergency. The res people will do all they can to accomodate. I say to call res is because they seem to know what to do in situations like these as opposed to the MPC.