As James Jordan points out (in the passage I quoted here), the communion of saints is not that I am connected to you and you are connected to me, but that you are in Christ and I am in Christ and we are united in Him. He is the connecting link between Christians. Jordan’s application had to do with the possibility of speaking to the saints and asking them to pray for us. But what he says also bears rich fruit for our comfort when we lose loved ones.
When a loved one dies, so much is left unsaid. We want to tell Grandpa how much we love him. We wish he could know what we’re doing. Sometimes, we wish we could ask his forgiveness for wrongs we’ve committed. But there is no indication in Scripture that our loved ones in heaven are now watching everything that we do, let alone that they can hear what we might say to them.
But then our communion with Grandpa was never first and foremost our family relationship or the fact that we could see him face to face or that the words from our mouths could reach his ear. Our communion with Grandpa was first of all in Christ: He was in Christ, and so were we. And that hasn’t changed. Jesus is still the connecting link, and Jesus does see what we do and hear what we say. Which means that if you have anything you want to say to Grandpa, you can tell Jesus about it and ask him to pass the message along.
Can Grandpa hear you? Scripture doesn’t say. But Jesus can, and he can and will pass on any message that he thinks it best to pass on. Which is a great thing to tell grieving grandchildren who wish they could say one more thing to Grandpa.