Musnad Abu Ya'la al-Mawsili 149:78

Suwayd ibn Sa'id narrated to us, from Malik, from Hisham ibn 'Urwah, from his father, from 'Aishah, that a man said to the Prophet, may Allah bless him and grant him peace: "My mother passed away suddenly, and I think that if she had been able to speak, she would have given charity. Shall I give charity on her behalf?" The Messenger of Allah, may Allah bless him and grant him peace, said: "Yes."