My DN is 9 and co-slept with her mum (my sister) until she was 2. Her dad worked away Mon-Fri and was often out/in the spare room at weekends and they separated when she was 18 months old. EXBIL was very abusive to my sister and had very little to do with DN. To be fair to him, he has maintained contact but also he has said it's so he can keep tabs on my sister and disrupt her life.
ExBIL has had a new partner for three years. For the past six months or so, when DN visits at weekends/in holidays, his GF sleeps in DNs room and DN sleeps with her dad. My sister is not happy with it as ExBIL is a heavy drinker and has sleep apnoea - DN is always completely shattered after contact and my sister thinks she'd get far better sleep in her own room.
She also thinks it's inappropriate as DN is beginning puberty and thinks she needs privacy. If he'd always co-slept and it was a difficult habit to break then fair enough, but to start it at her age seems strange in my sisters opinion. She always worries that he's Similarly abusive to his new partner and could be using their DD as a pawn in a game as not many partners would be keen on being kicked out of their bedroom for their stepchild.
I'm torn. I co-sleep with my 7 year old often but then I always have done. What do you think?