What fabulous comments on my last post...I received several in private email as well. As always, thanks to you all for the support.
I do feel it important to clarify, however, that my many theist friends are not at all excluding of me, or proselytizing, or in any way pushing me away. Many many have been so helpful, and supportive. I guess it's sort of a cultural difference...a different map of the world that makes me feel isolated. What they turn to for comfort is not comforting to me.
There has been the occasional acquaintance who says something useful like "How can you believe you'll never see him again? Wouldn't it soothe you to know that you'll see him again in heaven?" to which I (would like to) reply, "I'd like to believe he'll be alive in my Christmas stocking on December 25, but that doesn't make it so." The truth is that I don't believe I'll ever see him, hold him, talk to him again. I think when you're done, when the neurons in the brain stop firing for long enough, that you're gone. What many see as the soul, I see as physics.
In so many ways, I think this is liberating. As a commenter noted, there is no "why" in physics. There is no blame, there is no plan. There is random chance that a cell in Henry's brain underwent a genetic transformation after which it no longer obeyed the laws of it's fellow brain cells, and grew and grew and grew until it killed him. It happens predictably, based on probability. There's nothing and no one to be angry about. I got to skip that part of grief.
There is of course a flip side. When there is no god, no one skippering the boat, the question of futility looms large. Perhaps that is something that theists struggle with as well....my guess is that it has a different flavor.
I appreciate all of the support and suggestions, there were several leads I hope to pursue.