[@Raijinslayer]
Father-figure? Prepare to have terrible daddy issues. Rhett makes for a very bad parent. xD
He's more like an uncle who drops by on occasion to tell inappropriate jokes and unlikely stories, but leaves as quickly as he appears.

As for Nemu, I think she would have a hard time finding anyone else willing to take her in, especially after being labeled as a fugitive by the librarium. So her stay with the Cloud Chaser would be long-term, if not permanent.