Ruling on Designating Three Days for Condolences

Q: Is designating three days for condolences to the family of the deceased considered a religious innovation, and is there a specific condolence for a child, an elderly person, or a sick person whose recovery is not expected after their death?

A: Offering condolences is a recommended practice (sunnah) because it involves comforting the bereaved and making du'a for them with good. There is no difference in this whether the deceased was young or old. There is no specific wording for it; rather, a Muslim consoles his brother with whatever appropriate words are easy for him, such as saying: "May Allah improve your consolation, comfort your loss, and forgive your deceased," if the deceased was a Muslim.
As for if the deceased was a disbeliever, no du'a is made for him, but his Muslim relatives are consoled with words like those mentioned. It has no specific time or specific days; rather, it is prescribed from the time of the deceased's death, before the prayer and after it, before the burial and after it. Hurrying to do it is better, and it is permissible after three days from the deceased's death, as there is no evidence for a specific limit.