Not necessarily grieving, per se, but we often know people who—for whatever reason—will be alone at the holidays (recently divorced, live to far away from home to get there, etc). We always invite the singlets (and sometimes doublets like roommates or a couple that will still feel alone) to come over. It sucks to be alone when nothing is open and there is nothing you can really do but stay home and feel alone. So we try to make sure no one feels that way.