Am I missing something about the sister wasn't the 3 body's found the sister clutching the mom?
That's what I remember but her body couldn't be identified but the mom and dad could be.
Yes, that is correct.
But you know, peoples imagination...Mommy could have hugged another female stranger during their death.
Or she wasn't hugging anyone because plane crashes are violent messes, and he was told a story to make him feel better and cope?
It doesn't take much imagination to see this door was left open on purpose as it is a basic tenet of storytelling. It's a basic example of Chekhov's Gun. A missing/unidentified body means the storyteller is leaving the *possibility* of the character's survival open. It's story craft 101.
He wasn't there, all he knows 100% is that his mother and father are dead, and his sister's body wasn't identified. Anything beyond that is speculation or stories he was told by other people. If the plane crash was fiery then it is even more likely that it was a random person's body because bodies in fires bodies often meld (for lack of a better term) together and become hard to identify, there need not be any "clutching or hugging" involved and again, rescue works don't keep track of that kind of stuff when they are pulling bodies out of disasters and are just trying to save/identify people. It's likely that Nana told him that story, "Oh honey, yes they died, but she died in mommy's arms, they were all together..." When in reality they were probably bloody messes hardly near one another by the time of body recovery and the sister's body was missing.
Is it likely the sister is alive? Probably not.
Is it possible? Of course it is.
Watch any romantic soap opera tv show or Spanish telenovela and you can see these story lines play out all the time with even less reasonable possibilities foreshadowing the return than a missing body.