Posted about this before about a year ago, when my DH was shouting at DD and scared her. Things improved dramatically after that and he was really trying.
Now things have slid back into the old pattern. He doesn't open his mouth without nagging or criticising or telling her off. I don't think he's even conscious of it. So she gets defensive and starts getting annoyed. So he gets annoyed and has more of a nag. She shouts, he shouts, and it all escalates.
It's getting to the point where I worry about going out for an evening or a weekend away because I don't trust what's going on at home.