I have flown with people (RC) who announced it was their last flight many times. Some after that flight gave their stuff away at that time and some continued to build until the final day. One took everyone that was there to lunch and gave them his stuff. He said his day was probably less than a week away. He was right. I know a modeler that died going out to pick up their plane after a flight; having sudden cardiac arrest. That one is one a lot of guys said is the way to go. Really, no suffering. By the time someone got to him he was barely able to speak and had passed by the time rescue got there.
In a way, I am surprised this doesn't happen more given the average age of people in the 2 clubs I am in. The average has to be in the high 60s. Some, no matter their condition come to the field or what mobility devices are needed; wheel chair, crutches. electric wheel chair or oxygen tank.