Giving charity on behalf of the deceased

It is narrated from Sayyiduna Sa'd bin Ubadah (may Allah be pleased with him) that he set out with the Prophet (peace and blessings be upon him) on one of his military expeditions. Meanwhile, the time of his mother's death drew near, and she was told to make a bequest. She said: "What should I bequeath? The wealth is all Sa'd's wealth." So she passed away before Sa'd (may Allah be pleased with him) arrived. When Sa'd (may Allah be pleased with him) returned and learned of this, he said: "O Messenger of Allah! If I give charity on her behalf, will it benefit her?" He (peace and blessings be upon him) said: "Yes." Sa'd (may Allah be pleased with him) said: "Such-and-such orchard is charity on her behalf," and he named that orchard.
The chain of this hadith is sahih, but the two Shaykhs did not record it.

It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that a man said to the Messenger of Allah (peace and blessings be upon him) that his mother had died; if he gave charity on her behalf, would it benefit her? He (peace and blessings be upon him) said: "Yes." He said: "I have a fruit-bearing orchard, and I make you a witness that I have given it in charity on her behalf."
This is a supporting hadith that is sahih on the condition of Imam Bukhari.