My D broke up with her SO and her SO’s parents, with whom D had spent a fair amount of time with, sent her a text that was very kind. I don’t remember all the details but basically said what a lovely person she was, how sorry they were to hear about the break up and that the two of them were likely to have other relationships and life experiences ahead of them and that they wished her all the best. I’m not really conveying it well but it was very comforting to my D and she was touched. There was no ongoing communication; just the one time text exchange of one text each and I don’t know if the SO knew and/or approved it in advance.
I’m not advocating this; just sharing my D’s experience and how much she appreciated it.