You cheer them up by telling them that at least they don’t have to deal with [insert bad present from an ex here] and she doesn’t have to buy any extra presents this year.

If that doesn’t work, you base it off of their exes’ behavior: for example if they got sloppy drunk, you say that at least she doesn’t need to DD/babysit this year. If they were loud, you say that at least she’s not going to suffer permanent hearing damage.