DS7 has returned from his Dad's today with deep scratch marks all down his chest. My initial thought was that it was their new puppy, but on closer inspection they looked too deep, too sore and too far apart to be a dog paw. DS7 kept saying he didn't know how they got there. I eventually got it out of him that his step sister who's 8 had done it. There are also a few smaller scratches, one by his eye and another by his mouth.
I know step siblings can fight but i'm horrified by the state of DS7s chest. I don't have contact with my ex as he's controlling and awful to deal with. I get on very well with his partner (the 8 year old's Mum).
I text his partner to ask what on Earth had happened and her response what pretty much 'oh well, these things happen'.
What would you do in this situation? Leave it or message back something a little firmer?