The only thing I can think to suggest is just to be there for them, the surviving family that is, and to let them know you will be there for them.
Yes, be there for them, listen to them...
And take the time to cure your own grief to...
Taking care of you in this painful moment, to be able to be there also to the one who were is family, that you care about.
Hope that help in this sad time.
With you in mind and heart in this hard time.