I don’t suggest moving her back in so quickly if dad hasn’t attended any therapy sessions yet. And he needs to. 5 months is a long time and should have been a part of therapy by now, why hasn’t he? Just moving her in pretending nothing happened is worse than confronting the behavior and root problem and sounds like he’s avoiding it a bit and needs to step up not have your do it. Detach of bit and have dad take over this it’s not for you to be dealing with it’s mom and dads. While it’s nice she feels she can trust you and come to you like that there’s issues here especially considering there been abuse allegations by this child that aren’t true. Tread carefully. And I suggest if you do allow this child back to have you bases covered like installing surveillance and things like that in case you have to prove something which I don’t know about you but I wouldn’t want to live that way and would think long and hard about this. Have a game plan with therapist in case allegations arise again as we live in a time of “always believe the child ask questions later” and this could get a whole lot worse for you.