Comforting grieving people is a tricky business. In part it's tricky because dealing with anybody in any highly emotional state is a tricky business. But grief is made more difficult by the fact that those things that might be comforting to you may further aggravate the emotions of the person who you are trying to help.
Three years ago, my step-grandmother died. She had been deteriorating for several years due to Alzheimer's, and, as is often the case, was truly gone well before death. At her funeral and after her death, I was present for family members, and tried to be helpful. However, I know that I was not as comforting as many of the other people present for the simple reason that I never said nor agreed to anyone's assertion that we would see my grandmother again in Heaven. Most of my family members didn't notice that I wasn't joining in the after-life chorus, but a few did, and they were, not displeased as such, but clearly felt that I was not as helpful as I could have been.
Still, I felt, and still feel, that it was better that I not say anything that the person would likely find out that I didn't believe. That feels like a betrayal of the person's trust that could re-open wounds when the griever discovers that I lied, and is not something that I think is appropriate. It seems better to do what I can without lying, thought I know that int he short term this will not help as much as I wish.
On the flip-side, I often also find myself in odd and uncomfortable places when other people try to comfort me. Because I don't believe in an after-life, I often find myself frustrated when people try to assure me that I will see someone again in such a place. Of course, I realize that people saying such things shows a legitimate concern and effort to help on their part, and so I try not to be rude to them when they say such things. Nonetheless, it adds an additional frustration to the emotional burden of grief - and the more simplistic the notion of the after-life, the more infuriating it is*. These sorts of things may help soothe the pain of many people, but they simply leave me feeling as if I am being condescended to.
Just as I may not be helping to lift the burden from someone who does believe when I comfort them, when someone tries to tell me of the after-life they are adding an additional burden on my shoulders.
All of this creates this weird dance around grief. We wish to help, but those who are aware have to try to not condescend to or insult the grieving while also helping to share some of the burden of grief. Those who are unaware often make the plight of the grieving worse while trying to help.
*And the next person to spout that juvenile "Rainbow Bridge" claptrap to me is getting tazered!