What is the guidance for one who has not maintained ties with his parents for years

Question:
May Allah bless you. The last call is from al-Madinah al-Munawwarah, may Allah bless its resident, Muhammad (peace and blessings be upon him), the best of prayers and the most complete of blessings. Brother Abdullah, please. Peace be upon you and Allah's mercy and blessings. And upon you be peace and Allah's mercy. Yes. Can I speak to the Shaykh, may Allah prolong your life? Yes, the Shaykh is listening to you, please go ahead. Long may you live, I have a relative who is a close kin, and they have cut off the ties with their parents, and there are many other things, long may you live. Regarding the parents, meaning they do not ask about their parents, perhaps for five or six years, they do not even say "peace be upon you" to their parents. So what is their ruling? And their measure in harm is greater than this. May Allah reward you with good, thank you, Abdullah.

Answer:
This, my brother, is undutifulness to parents, and it is among the major sins after shirk (associating partners with Allah) the Exalted. It is obligatory for you to advise them and admonish them in this matter, yes.