Is it considered a sin to confront a father who curses his children, wishing them to go away, knowing that he is religious and ill-tempered and cannot stand their presence?

There is no harm in offering advice to one's father gently and kindly, just as Abraham, peace be upon him, did with his father. The Prophet, peace and blessings be upon him, said: "Religion is sincerity (advice)," and "I pledged allegiance to the Messenger of Allah, peace and blessings be upon him, to establish prayer, give zakat, and advise every Muslim."

You should also remind your father of the importance of being merciful to his family and children, citing hadiths that encourage mercy, such as: "Do I own it if Allah has removed mercy from your hearts?" and "He who does not show mercy to people, Allah will not show mercy to him." And the saying of Umar ibn al-Khattab: "Indeed, I am pleased when a man is like a child among his family, but when a need is sought from him, he is found to be a man."