What's the best or most appropriate way to respond to a parent who has lost a child especially at a young age?

Anybody in the birth story thread is going to know what lead to this, but I just wanted to get a few thoughts on this. I’m not a parent, but it seems thats got to be one of the hardest losses to deal with. As a parent or as a nonparent how do you respond to someone who has lost a child or as a grieving parent what helped you get through it. If it was fairly recent and/or still too painful please don’t respond. I’ve been through enough of similar things to know it takes a lot of time to even cope with this.