Young autistic child hurting parents new problem

[Sweetums]

You have to be firm and consistent if they are hard no's you have to back this up consistently and firmly. We have always had a "no hitting in our family" rule, and "No swearing" from a very young age. DS13; some of the things we allow him to do, for instance, bum and poop are words he uses for stimming. pick your battles; it's better than the alternatives.
It doesn't work all the time; but it is better than others have it.
We also have DS9 who feels he is being left out, as DS13 doesn't want to play with him, or often doesn't want him in his room or to play only on his terms. so there is quite a bit of retaliating to work with; again we are consistent and firm.
When working with the psychologist, we were told to not try and talk when they are angry and stressed, wait for them to calm down and then discuss it, (discussing it at this point is likely to take them back up to where they were; keep reassuring, and calming them down); I I think this has led to him being able to calm down now (with us still coaching him) use social stories (I still don't get these).
You won't fix it in a day, a week, a month or even a year, or even 4 years, but it does get better, and you can look back and see how far you have come (other things not so much).
It's ok to be angry and get angry, it's the way they are taught to deal with it that matters. and above all do not escalate the situation, we spent years of shouting him down, and him shouting back this will not help, and makes it worse. if your daughter is under 9, I would suggest trying to get seen by the child psychologist team (not chams) I don't know what area you are in, but giving them a "tool box" to use and knowing what techniques you can use really help.