My dad died when I was a teenager. He had a heart attack. Since he was gone long before my kids came along, they know of Papa Rick, but have never met him. He is often talked about, they come to his grave with me and they know that he died "because his heart didn't work anymore". We have always refrained from telling them someone died because they were old or sick - and try our hardest to tell them the truth.
Last week, Mr. K spent some time with my mom. That night, when I was putting him to bed he was talking about Papa Rick, and how he was dead. We talked about how it made me sad, and he was sad too. Then, he told me he had to go to the basement, to Daddy's workshop. He had to get a screw driver, and he was going to fix Papa Rick's heart so he wouldn't be dead anymore.
It was the most adorable thing - he was certain that daddy's screwdriver could fix it - because of course, if something breaks in the house the first thing hubby does is try and fix it.