Regret

People say not to live life with regrets, well, I have one today. I found out that a long time donor of the organization I work for passed away recently.  I didn't know him too well, but he always came by to drop off his donations in person.  He was nice and sweet to me.  The thing I regret is that I realized a little while ago that I hadn't seen him in a while and he stopped by pretty often.  I thought about calling him to see how he was doing, but I felt uncomfortable with it since I didn't know him that well... if he was sick, I didn't want his family to think I was being nosy or something.  But now, I wish that I did and not care about what other people thought.  Could have, should have, would have...