I've seen a bunch of people put Jackie on their thumbnails and it made me wonder if Jackie is actually in the game, because I haven't seen him when I played it, even though I got the ending and everything.

If he is in the game and it's something cool to find, don't spoil where he is in the game, just say "yes he's in the game", because I'd love to find him myself!

If it's not that big of a deal though, for example if he's just standing in some corner, not doing anything, then you can tell me his exact location, so that I can quickly check him out and then close the game again