From the article, Rose just mentions that was the timing. At least to him that was the timing. It does not sound like he ever heard Dastrup or anyone else directly say that Dastrup was leaving because Childs was coming back. I doubt Rose actually believes that either. I do think he was dumbfounded by Dastrup's decision (as am I frankly).

My personal feeling is that Dastrup made an emotional-visceral decision. I also feel like, for all of Rose's great traits, managing minutes for the end of his bench was never a priority. We saw it with Dastrup two years ago. We saw it with Baxter this year. Those players got really frustrated by the lack of playing time.