question #1 Sahih al-Bukhari 1855, Book 28, Hadith 35 : What guidance does Islam provide regarding performing Hajj on behalf of someone who is unable to do so due to old age or infirmity?

Al Fadl was riding behind the Prophet (ﷺ) and a woman from the tribe of Khath’am came up. Al Fadl started looking at her and she looked at him. The Prophet (ﷺ) turned Al-Fadl’s face to the other side. She said, “My father has come under Allah’s obligation of performing Hajj but he is very old man and cannot sit properly on his Rahila (mount). Shall I perform Hajj on his behalf ? The Prophet (ﷺ) replied affirmative. That happened during Hajjat-ul-Wada’ of the Prophet (ﷺ).