Sayyidah Aishah (may Allah be pleased with her) said that a man said to the Prophet (peace and blessings be upon him): "My mother has died. Had she been able to speak, she would have asked for charity. If I give charity on her behalf, will she receive the reward?" He (peace and blessings be upon him) said: "Yes."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 7103