I am sorry for your loss.
If you already referenced that in your RD supplemental essays, no, do not send.
And if you did not include that in your RD application then I would hold off sending anything else right now. If you are waitlisted maybe then you can share some more. If you are interviewed maybe you can share some appropriate personal information at that time.
More importantly, understand that Stanford is a high high reach for all. Unless you have a major hook REA or RD will not make a huge difference.
Where else have you applied and did you have time this past fall to fully research your safeties? That may be a better use of your time as you wrap up senior year. Also, find some time for self care. This has been a stressful time for you.