Not dispelling the notion about Kronii and Sana's closness, but I am pretty sure the tweet you are referring to is related to Sally's wedding. Kronii had attended Sally's wedding in the same time-frame, and has consistently referred to Sally as a good friend. Sally had also gotten pregnant a few months after the wedding, and surprise surprise, Kronii is now an aunt. The tweet in my eyes reads more about the wedding, since I am unsure what happened with Sana's RM that would relate as well with the tweet in that time frame.