Very sad but looking back maybe not the wisest move of social services to take him away from the foster parents who it appears from your subsequent posts he had a good relationship with at the age of 5 when he was probably starting school so loads of new scary changes to cope with and give to a single mum (You say foster parents so presumably a Dad too)
I feel for your daughter but she has tried for a year and he’s spent a year telling her in the only way he knows how that he doesn’t want to be with her he wants to be back where he was familiar (you don’t say how long he was in the foster home but he sounded settled)
I think this is the best solution all round especially if it’s long term fostering
This child unfortunately has maybe been ‘given’ mental health issues by this whole uprooting Taken from an obviously harmful situation into a place he was settled and happy (you say none of this occurred in the foster parents home) had a year of fighting to get back to where he wanted to be which he has accomplished to the detriment of your daughter He did not bite and kick and abuse your daughter because he didn’t like her but because he had been taken from a familiar situation against his wishes I don’t think it shows this boy as having mental health issues I think it has shown him as a ‘determined fighter’
I hope your daughter recovers and I hope he settles back where he wants to be
Is it me or am I getting mixed messages