My husband does the same kind of stuff. Although he would rarely if ever notice what they're wearing. He says other stuff though that is just right off the wall sometimes.
Don't know what to say to you except to try talking to him in private about how it effects the children/the household. I talk to mine in private and he stops, at least for a while. These kind of people need to think about their words and they need to actually want to examine themselves. Ask him if he thinks he's perfect or what. He needs to put himself in their place. Think of himself when he was a child. These are important little things everyone should do from time to time.
And if he was treated this way as a child, how does he think it's helped him. Has it made him better or worse for it? Can he come up with better ways to express himself? What's he afraid of? Are these things really that important to make the child feel bad? So he's going to make his child feel bad over something so not worth anything, over something stupid just because of his own hang up?
Maybe you should write it out, make a list so to speak of how this affects the atmosphere and how he can practice positive statements. He wants the best for his kids, right. Well, it begins with him.
Don't know how far you can get with him even if you plead a good and honest case but I'd keep working at it. I know my husband can be pretty stubborn. But he will stop for lengths of time
The best to you with this