One Piece which he has not watched
And Supernatural which I have not watched (he made it up to season 9)
One Piece we're just starting Water 7 and have reached the point where Usopp confronts the Franky family about the money.
Supernatural we're about to start the second to last episode of Season 3 (no spoils pls).
One Piece has been fun, especially seeing the first time reactions of someone watching it for the first time. I usually never get an opportunity like this.
Supernatural has been a lot of fun as well. The quirkly 2000s style is very endearing to me. And I feel that Sam and Dean are fantastic main characters. I've heard that it declines in quality after a while, but unless it's unwatchably bad I'll see this adventure through the end.