Haven't read the whole thread so I answer this with slight dread
But the answer must be 2 I'm sure it's true
The grandfathers father might not be fishing with them but that does not change the fact that he definitely is a son to someone. The other is his son who still likes to have fun. He has a son who is perhaps somewhere with his great grandfather while the two go fishing. Picture it that way. Great grandpa is with great grandson while son and grandpa go fishing.
But the answer must be 2 I'm sure it's true
The grandfathers father might not be fishing with them but that does not change the fact that he definitely is a son to someone. The other is his son who still likes to have fun. He has a son who is perhaps somewhere with his great grandfather while the two go fishing. Picture it that way. Great grandpa is with great grandson while son and grandpa go fishing.