DS is only 2. He had a long grizzly morning today while my parents visited, including a couple of tantrums, not eating his dinner and general whinging. All because he was tired. Me and DM were largely ignoring the behaviour, I was cuddling him and carrying on as usual where possible, but while I was upstairs changing DD I heard my dad telling DS he was horrible, several times (DS was just whining back at him). I'm not sure whether DS understood, but I was horrified.
However (and this is where I'm a bit stuck...), I didnt say anything, and I don't know how to address it now, but I don't want it to happen again. In my parents' eyes I'm a 'good girl' (I'm sure they think I have 'weird ideas' about parenting - cosleeping, feeding on demand, positive discipline etc - but I've never, ever challenged my parents, in fact have gone too far out of my way to please them in the past). How do I tell my dad i don't want him speaking to my child that way without either damaging all the relationships involved or opening a whole other can of worms about how much of a hold over me they have and how much I resent that?
I should probably just grow a pair and tell him to button it in future, but that's very new territory for me. However my DC come first so if that's what needs to happen I'll do it... Any thoughts?