My late husband had depression at one point (which he didn't blame me for) and I'm truly shocked at some of the posts on here. It's real, and it's potentially serious.
But back to your situation @Needacupofteaandcrackers . No you're not to blame, and your children need a normal family life, which included chatting about their day over a meal.
But your DH's thinking is disordered, and he needs professional help. You say that counselling wasn't helpful so he doesn't want it, but is he on medication?
Whatever he thinks of you, he also has children and at some point he has to understand that just as he thinks you're causing his depression, his behaviour around the house is affecting his children, and he needs help for himself and for them.
My DH desperately tried to keep family life normal when he was ill, but there were occasional episodes that affected our kids (who were in their late teens when he got ill) and I hate that they happened, as did he. But he got all the help that he could because he wanted to be well and a good dad.
It fits without saying though, that any expressions of how you feel about your on laws need to be kept on the back burner.