Yes the UK school noticed he was behind in maths and gave him booster lessons and he is now up to speed.
He appears to be socialising well in UK school but did so also in Berlin where my son first worked for 5 years. It was when my son moved to Stuttgart last year and his job was not going well that my grandson struggled. My son had to transfer to Frankfurt and my d.in law just couldn't move and start all over again, she's frightened, we think . We do sympathise with my d.in law but it's hard to see the family apart and worry about the boys mental state.
Thank you for mentioning the family counselling; I was able to mention this to my d.in law this afternoon, and I think she will follow it up, as I said that it was very difficult for me or her mother to advise her; she (they) needed an impartial opinion. My son has asked her over the year to think about attending 'Relate' together, but she didn't seem keen at the time, but she seemed to respond favourably to 'family' counselling.....fingers crossed, thank you so much.