Because most of us are so uncomfortable with death, we look for ways to divert ourselves when death stares us in the face. I am not referring to moment-of-truth encounters in which we must face our own inevitable death; I mean instead the sense of uneasiness we feel when called upon to comfort those who have been wounded by the death of a loved one.
Perhaps the best guidance one can find is in how we express the role which friends and extended family play in the mourning process. It is common to refer to a visit to the mourner as "paying a shivah call." Aside from the social connotations of the phrase, it makes the visit sound more formal and less helpful than tradition expects. The Hebrew term for such visits is nichum aveilim, comforting the mourners. Your presence should bring comfort to those who are bereaved.
But how? Fortunately, one piece of advice and plain common sense will guide you. The piece of advice is this: focus on the needs of your friend, not on your own needs. While we each need reassurance in the face of tragedy, our needs are theoretical, while the mourner’s needs are practical. The wisdom of our communal approach to mourning includes the vehicle for addressing our own needs as well.
The door to a shivah house is generally left open so that the mourner does not have to "admit" visitors. Upon entering, the visitor should wait to be greeted by the mourner, who may not wish to speak. It is appropriate to offer the traditional message of comfort, hamakom y’nakhem otkha (for a man)/ otkah (for a woman) b’tokh sh’ar aveilei tzion virushalayim, "may God comfort you along with all mourners in Zion and Jerusalem," but a simple "I’m sorry" is also appropriate. The direction of conversation is up to the bereaved, though it is appropriate to ask about the deceased and the qualities of his/her life. Sometimes the conversation will be light-hearted; sometimes it will be dark; sometimes it may seem to have nothing to do with the grief which precipitated it. Those decisions are up to the mourner. It is not appropriate to decide that the mourner needs cheering up nor to chastise a mourner whose laughter brings comfort.
To address our need to affirm and nourish life, tradition gives us the chance to care for the mourner. Providing food to a mourner’s home is welcome. Often more welcome are paper goods, trash bags, coffee or other soft beverages, light cleaning supplies. When you visit, the offer to help straighten up, take out the trash, fill toilet paper dispensers or sort the mail may be very welcome. Engaging children may give parents a welcome break; walking the dog or feeding the cat may be helpful as well.
But mostly, it is your physical presence which is most comforting. Everyone is willing to come for a minyan and to be part of a community of support. Mourners are often especially grateful for visits during long afternoons, when the emptiness of the house stands in stark contrast to the gatherings for prayer and the weight of grief is most difficult to bear. God gave you shoulders, ears and tears as standard equipment. Sharing them with others who are in need is the best form of gratitude.