Doesn't have to be in Suikoden 2's timeline. I think the first game had the most elderly playable characters in it, though. Kai, Hellion, Liukan, Fukien, Mace... It's kind of annoying that Max was never usable in combat.
In 5 you needed to have an elderly character in your group who was at a high level to recruit Genoh, but options were quite slim. Alhazred, Levi and Galleon. Sairoh and Raja couldn't be used. Jeane, Eresh and Zerase are old but ageless. Oh, and I think some of the dwarves and beavers might have been older folks.
This just goes to show that we need more oldies in Suikoden games. They needn't all be human either. Give us some old kobolds and wingers.