FIL is immature. People tiptoe around him because he has a quick temper. Recently FIL seems to have decided DS needs shaming, so he’ll try to start an argument.
For instance, FIL will announce out of the blue that the music DS is listening to is “rubbish”. I’ve told DS not to rise to it but, he’s 12, sometimes he does. It’s as if FIL sees a young man and wants a fight 
DH is not on the scene. MIL just keeps out of the way. I don’t want to go and see them anymore because chances are it’ll end in a fight. FIL used to hit DH when he was DS’s age, I don’t want that to happen to my son.
It’s only me and DS, I feel like just moving away and not telling them where we are.