Do good death signs, such as a sweating forehead, a smile, and asking for water, indicate a good ending, despite some idle and vulgar talk uttered just before death? And will the deceased be forgiven in this case?

We ask Allah to grant your father forgiveness and mercy. He will not be held accountable for any words he uttered if he was overcome by his mind and unaware of what he was saying. We hope that Allah will forgive him and overlook his misdeeds, and that the sweat on his forehead is a sign of a good ending. There is no need to worry, as your father has gone to the Most Merciful of those who show mercy. You should strive to supplicate for him and seek forgiveness on his behalf, as he will benefit from the acts of worship you perform for him and dedicate their reward to him.