Wow Gordon, I'm really sorry to hear this. Losing a friend is a bad deal, but the way your situation played out...I'd say I'd feel like I should have done something more too. I'll keep you and your friend's family in my prayers.
You just never know when your 'number' is up. As cliche as it sounds, live each day to the fullest and enjoy life. The older we get, the closer we get to finding that 'number'.
On a similar topic, I just lost my grandmother tuesday morning, so I completely feel your pain.
Hang in there and keep your chin up, thinking of the good times you all shared.
Lot's of really sad situations happened to many of you. Seriously, enjoy each day and do what you want to do when you can, because you may not ever get the opportunity.