Thanks for your words of condolence and advice. I had not not heeded this advice to wait until I have calmed down but had called my parents back and had told them what I think of their behavior. But there are walls around them. They say we do not have a common bases and do not match. Of course, they are also in a difficult situation and I should have waited.
I have also given up the hope that they awake. My father was inactive for some time due to issues with his fellow elders but he went back and is more convinced than before. I am afraid if he or my mother should wake up from the cult it will be too late due to age to have a serious talk.