"The wife of sinan bin Salamah Al-Juhani ordered that the question be put to the Messenger of Allah about her mother who had died and had not performed Hajj; would it be good enough if she were to perform Hajj on behalf of her mother? He said: 'Yes. If her mother owed a debt and she paid it off, would that not be good enough? Let her perform Hajj on behalf of her mother.'''
Sunan an-Nasa'i Book 24, Hadith 15