The thing is, I do think Kris and Sans could get along very well because they’re very similar people. They’re both the more reserved siblings of an extrovert, they’re both very private people who have a lot going on that we never really see in-game, and they both have a love for pranks and practical jokes. Sans also did help out with chores when he spent the night at Toriel’s, so he’s clearly very respectful of the Dreemurr household and he isn’t just some bum Toriel brought home because she thought he was funny. I do think they could grow to appreciate each other over the course of Deltarune, and I think it could be an interesting direction to take things, but also, Kris is going through A LOT, and while Sans Deltarune has no way of knowing this, (Undertale is a bit of a different story since that version of Sans is Built Different) it’s just a really bad time for him to be getting involved with the Dreemurrs, especially when Kris is still reeling from their parents’ divorce.