I'm not a man but will put in my 2 cents worth. How he talking to you & the kids is unacceptable, which you are aware of & have asked him to stop. Unfortunately, he will not listen. You mention his temper is getting worse - if you are afraid for your safety or your childrens -you need to get out of that house now. But if you have concerns & your husband is with them all day - you need to look out for them. Hopefully your situation is not that extreme.
There are obviously communication issues here & until those are resolved, I don't see this situation improving
So what to do? I would suggest therapy to your husband, let him know you sense his frustration with the kids, that you appreciate him helping you with them, etc. But that you have realized that any time you try to discuss your parenting styles it becomes a road block. Express your desire to try to work on things together & invite him to join you . Hopefully he will agree, but if he does not I would seek assistance on your own.
Just a few more ?'s, does there seem to be a defined start date as to when he started acting this way? Was it when he went back to work? Is he working now? I would imagine your kids are in school, so does he care for them afterschool?
hopefully you can find a way to open the lines of communication so this situation can improve for you all. good luck