Sometimes in the growing up years a child who has been peaceful and cooperative seems to become angry and reactionary about everything. This is often a shock to the parents. They think, "What on earth has happened to my easy-to-get-along-with child?" We know this often happens in the teen years. There is even a term called, "Teen Angst" for this change. But this can surface at any age. What can parents do about it?
First: Focus on keeping their heart through it all. That will mean a lot of listening and not arguing back on your part. Say back to the them what you think they are saying and ask, "is that right?" Affirm your love right while the argument or acting out is going on and make sure you mean it even if you don't feel too loving at the moment.
Second: Find out where there is wounding. Ask questions and listen as best you can between the lines. Also step back and observe. Is someone in the family always trying to run over the child's true rights and therefore the child feels violated? Is the child growing into another season of life and they need a change somewhere that recognizes that? I know of a family that had three children, a first born daughter and two younger sons. The daughter seemed to suddenly change from a cooperative, helpful sibling to one who was screaming at and pushing her brothers and being angry at the parents for anything they asked of her. As her parents stepped back and started to observe her they realized she was starting to head toward the teen years and needed more privacy and and some personal focused attention. They resolved the issue by re-painting her room and letting her pick out the color and building some storage for her to help her keep her room neat. They also made a rule that the boys had to knock on her door to get permission to come in. With this kind of protective attention she was able to let go of most of her frustration over her rambunctious brothers and turn back into the sweet, helpful child she had been.
Third: Set up projects that increase personal growth in the area you have discerned is causing the problem. For this young girl, a secret project between her and her mother was set up to do a nice surprise secretly for each of her brothers. Having her rights protected was good but she needed to go the extra mile and give to her enemies to become totally emotionally free. This family is still working on that part.
Fourth: Give the process time to work. You may have to build some trust that was broken and that doesn't happen immediately. So the character qualities of consistency and perseverance have to be practiced by you.
You can win back even an estranged, angry adult child this way but it takes a LOT LONGER. So hang in there. I have seen success even after the parents had passed away. Yes! I said it is a long term process. So just hang in there!