DH has a DD from a previous relationship. He and DDs mum have always remained civil, and she is married with 2 more children. This weekend it became apparent that the husband has stopped DD from visiting her nan ( the exes mum) as 'she spends too much time there' and should be at home with their family. The nan is upset obviously, there hasn't been an incident or argument. The husband just appears to be jealous. DHs mum is telling him to have a word, as, as she puts it 'its none of Other Mans business' what dd does. I think DH should not get involved just to keep things friendly. Opinions?