It was narrated from ‘Abdullah bin "Abbas or from al-Fadl bin "Abbas that

a man asked the Prophet (ﷺ): O Messenger of Allah, Islam has come and my father is an old man and cannot sit firmly on his mount; can I do Hajj on his behalf? He said: "Do you think that if he owed a debt and you paid it off on his behalf, would that be acceptable?" He said: Yes. He said: "So do Hajj on behalf of your father.”