On page 806, Nick describes the way that Matty's kids felt at their Grandmother's funeral when they saw their dad for the first time as a brother and as a child. This same logic seems to apply to other characters. There's Nick the guy who has two kids and a wife and a job, but hidden beneath that there is Nick the murderer who his wife doesn't know. I think it's really interesting to think about the way that Nick may be a father and a husband to the world, but he will always be the murderer in his heart.
DeLillo's novel has been about of an individual's different/secret role (ie. Marian the suburban housewife....drug abuser???) is really poignant in this part. I related a lot to this paragraph because I remember feeling the same way Matt's kids did at a funeral I went to.
I also think it's interesting that Nick really isn't either of these extremes-- a husband/father or murderer. He says in the epilogue that the role of father, grandfather and husband weren't really his, that he just "filled out the forms." And the murderer he imagines himself to be is also fabricted. He keeps the secret of the murder hidden because he imagines it and himself to be more dramatic/horrible/movie-like than either really are; the murder was more or less an accident, and he really isn't as tough and gangster-like as he'd like to think himself to be. But then he is neither who he thinks he is nor who he is role-playing, so I don't know who he is! He's lost, I guess, which could be a commentary on the fragmentation of everyone growing up in the Cold War era.