Thank you Marty. And to expand on that, I don't think he died in the jump, without those things you mentioned, or grieving loved ones drawing attention. Nobody falls off the face of the earth like that... If he did die in the jump, it is possible his kin were sublimely naive, enough so that it would overcome the desire of importance, being, that it was their relative who was Cooper. But I still think over time that still would have surfaced...
HOWEVER... A foreign Cooper, say, from Quebec, and the relatives could easily have been oblivious to the caper. Having lived overseas for many years, I realized how insulated our media bubble is. Had he been foreign and perished, the lack of kin outspeak is very plausible.