OP, I didn’t mean to be harsh by bringing up past threads or comments; MN is a place where a lot of us bring our problems so of course, we may look like we’re going from one disaster to the next sometimes, because that’s when we need the advice and support of (mostly) other women. The problem is when you start going outside the norms, like using corporal punishment on your children, that someone needs to say something, I think. I’m very sorry that your parents hit you, VERY sorry, and unfortunately, those who are hit are probably the last people who want to hit their children and yet they are the most likely to do so. And while it may seem unfair, the same parents can have a very different relationship as grandparents since they don’t discipline your child.
While I don’t know exactly what happened the day your son left for their house (whether you just said, “DS, can you please tidy up,” and he went, “No! I don’t have to do what you say! I’m going to the GPs!” And then slammed out the door), but if it really was just him refusing to tidy up, then I doubt him moving out and living with the GPs will be a good solution for either of them, as they will have to come to terms with each other and him needing boundaries, like you have said.
Unfortunately, it does sound like your text has made a bad situation worse. I am NOT trying to be unkind, but what good did you think the text would do? You started this thread because you feel your parents have been extremely harsh and completely misjudged you as a parent, yet you think they would give you the benefit of the doubt over a confusing text message. I think maybe you’re under an incredible amount of stress right now, and it’s making everything more difficult. To fix this situation for now, I agree with Elieza. I’d sit your son down, and basically tell him what she’s written, because it sounds about right to me.