Why was Grandpa Gohan never revived with the Dragon Balls? I was recently re-watching DBZ dub episode 171 about how Gohan got his name, tree he crashed through as a kid etc. And a thought came to mind. 

Why didn't we ever see Grandpa Gohan in DBZ? I mean there were plenty of scenarios where goku could have found him in other world or the Z-fighters could have revived him with the Dragon Balls. 

And in addition to that IIRC, They wished for all the humans killed by the saiyan invasion to be revived, wouldn't that also account Grandpa Gohan since he was accidentally killed by Goku in his oozaru form?
He expressed that he does not want to return to the world of the living ones. Goku fought against his grandfather (masked fighter) at a tournament hosted  by Fortuneteller Baba. After revealing his identity to Goku, Upa (the boy whose father was killed by mercenary Tao and Goku went on a quest to gather the Dragon Balls and revive his father) asked him if he want to be revived instead of his father, but Gohan replied that there are a lot of "babes" in the after world and that he would like to stay there.



The chapter in question is 108 from the original Dragon Ball.