The son's ill-mannered behavior toward his father

The brother Ibrahim sent a message from Ta'if saying: A dispute arose between my father and a man over a piece of land, and it is not known who is more entitled to it, my father or the other man? So the people of good came to the problem and wanted to reconcile them, but they were unable to do so. My father insisted that the land is his, even though it is not entirely his right. I tried to convince my father to accept a settlement or to take an oath from his opponent, but he rejected all attempts. So, out of anger, a word came out of me, and I said to my father: "You are a liar." What is the ruling on that, and what is its expiation? May Allah preserve you, and peace be upon you and Allah's mercy and blessings.
Answer: You must repent to Allah for that and seek your father's forgiveness. You must seek Allah's forgiveness and repent to Him for this confrontation. You must seek your father's pardon and ask him to forgive you, saying: "Forgive me, my father, for it was a slip on my part, and may Allah forgive you."
You must also advise him if you know that some of the land is not his. You must advise him and explain to him the reasons that made this thing not his, but rather his opponent's, for this is the truth. The believer speaks the truth about himself, about his father, and about others, as He said in His great Book: [Surat al-Nisa: 135].
So the believer speaks the truth about himself, about his father, and about his mother, but in a good manner and with a good style, not with ugly confrontation. You say: "My father! I have knowledge, I testify... or so-and-so told me, or I learned such and such." You advise him between you and him, so that he may be guided, if Allah wills, and so that he is convinced by the truth, and so that he gives the right to its owner, without confronting him in a way that is ill-mannered toward him and disturbs your relationship with him, for this is not befitting of a son toward his father.
So you seek the forgiveness of Allah, Mighty and Majestic, and repent to Him, and seek your father's pardon. This does not prevent you from advising him and testifying to the truth, even if it is against him. And Allah is the Helper, and He is the One who grants success, and there is no power and no strength except with Allah. Yes.