When the parents behave irresponsibly towards their children during their time of upbringing and also in their later stages of life , it is quite normal for the children to develop hatred towards their parents . So how should the children look after their parents and how to approach them without hurting them and how to maintain Sabr in these type of situations ?
وعليكم السلام ورحمة الله وبركاته
Yes , it is true. As you mentioned it is understandable that if the parents neglect the responsibility of providing good education for their children and taking good care of them , the children may grow up in a rebellious manner. Even though it is understandable it is not an excuse or justification for behaving wrongly with their parents . Because if the children grow up as Muslims , they must search for the ways of righteousness and guidance in the Deen and ( other people/things ) in the Dunya as well . So if they did not find it from their parents when they were young they should find it from the texts of the Quran and Sunnah as they grow up. This is the meaning of the statement of Allah عز وجل in Surat Al-Fatihah : اهدنا الصراط المستقيم ( Guide us to the straight path ) .
Therefore , do not think that every righteouus person is guided only because of the proper upbringing of their parents . No , this is not the case . Rather , many of them became rightly guided and upright in morals because of a verse from the Quran or a Hadith from the Sunnah or an advice from an advisor and so on.
The scenario mentioned in your question makes it obligatory for the parents and their children together to return to Allah عز وجل . This happens by way of striving to reform their selves based on what the Book and the Sunnah necessitates . And the first step towards that is to sit with advisors who have both knowledge and experience so that the situation and the problems are presented to them in order to rectify them in the proper way .
They all have to make a lot of Dua that are mentioned in the Quran and the Sunnah which lead to the rectification of one's situation, destination , family and offspring . Also they should hold on to patience and from the things that help them to be patient is knowing that they are being trialed and tested by Allah عز وجل , and there is no success in any trial except with patience like Allah عز وجل said { یَـٰۤأَیُّهَا ٱلَّذِینَ ءَامَنُوا۟ ٱصۡبِرُوا۟ وَصَابِرُوا۟ وَرَابِطُوا۟ وَٱتَّقُوا۟ ٱللَّهَ لَعَلَّكُمۡ تُفۡلِحُونَ } [ O you who believe! Endure and be more patient , and fear Allah, so that you may be successful ]
And Allah عز وجل knows best .