The ruling on one who forgets the prayer upon the Prophet (peace and blessings be upon him) in the funeral prayer

Question:
He says: Honorable Shaykh, may Allah grant you success, a person prayed over the funeral and forgot the prayer upon the Prophet (peace and blessings be upon him), making the second takbir a supplication for the deceased instead. What is required of him?

Answer:
If he remembers while he is still in the place, he should return and complete his prayer by reciting the prayer upon the Prophet and then the taslim, if he is still at the standing place. But if he has already left and gone, the matter is ended. However, he will be rewarded, if Allah wills, for his intention.