Mary, that's a terrible tragedy. My heart goes out to your friend and her family.
Just a few days ago, I unveiled a potsumous portrait. The piece and my thoughts on the inherent sensitivity of the process can be viewed here:
http://forum.portraitartist.com/showthread.php?t=4274
I had a few photos as reference, but the best one was an official high school photo - which was the technical equivalent of a "Sears portrait". And even though this wasn't so great, and all the rest of the shots were point-and-shoot frontal flash, the consistency of her features and expressions seved as an excellent gulideline.
Though it is obviously a terribly sensitive issue, in the interest of your success with the quality of the portrait, I'm certain the family will gladly loan you the materials you need once you explain to them the necessity of such reference.
Best,
Rob