You've listened and offered support, now step back and allow your h to work thru the shock of his co-worker passing away. There's no telling how your h will deal w/this shock. He may or may not attend the funeral or even want to talk about it further.
There's nothing more you can do at this time. Follow his lead, i.e., if he wants to talk about it further...just listen. Don't push him to open up...he's got to do this on his own. They have a difficult time dealing w/mortality, so I wouldn't be surprised if he opts not to discuss it.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
