I recently asked about books about adoption to help my 3.5yo ds understand his new cousins as he seems to currently be a little withdrawn and unsettled which has coincided with a new awareness of 'family'. He has now also begun asking questions about why his half sister sometimes lives with us and sometimes with her mummy. Basically he misses her when she leaves and is struggling to understand why she has to go. Anyone with any experience of this or know of any children's books which might help his understanding of the different types of family there are?