To my knowledge the rules for both changed, for Sleep in 1997 and Confusion in 1999, but I can't figure out how as I don't understand Japanese. Thank a lot for any help in advance!
Edit: This Information comes from https://wiki.xn--rckteqa2e.com/wiki/ポケットモンスターカードゲーム
Based on Google translate, it seems like sleep worked exactly the same as paralysis - making Base Set Haunter a very powerful card. But I was hoping someone could confirm I understood this correctly.