What is the method for the two rak'ahs of prayer, which, if gifted to the deceased, God will send him a thousand angels, each carrying a gift for the deceased to enjoy until the Day of Resurrection, and how can these two rak'ahs be gifted to the deceased?

Scholars have agreed that the reward for charity and supplication reaches the deceased. However, they differed on whether the reward for prayer, fasting, and Qur'an recitation reaches them. The madhhab of Abu Hanifa and others holds that it does reach them, while Shafi'i and Malik are of the opinion that it does not. It is permissible for a Muslim to perform supererogatory prayers and dedicate their reward to the deceased. As for the hadith mentioned in the question, no origin has been found for it, and it is likely fabricated.