Is the Prophet (peace and blessings be upon him) alive when one greets him in his grave?

The questioner : The angels conveying the message to the Messenger (peace be upon him)... his current state is that he is dead... does conveying the message mean immediately?

The Shaykh : Do you mean: does conveying the message mean immediately?

The questioner : It means immediately.

The Shaykh : Immediately, without a doubt, yes.

The questioner : Okay; so how does he hear if he is dead...?

The Shaykh : First of all, his death is not like our death. We have a sound hadith, of course, in which the Messenger (peace be upon him) said: . Also, this is another piece of evidence: it says "reaches me," not "I hear." . They said: How is that when you have become dust? "Armat" means you have become crumbled dust, meaning: . They said: How is that when you have become dust—crumbled dust? He said: . So the bodies of the prophets do not decay, do you see? This is one point.
The second point is that the soul is not only for the prophets, but also for the martyrs, and not only for the martyrs, but also for the righteous believers. There is a connection between their souls and their bodies, especially those like the bodies of the prophets, which remain, what? Fresh and green. But we do not have a text stating that a body other than the bodies of the prophets remains preserved.
The point is: in answer to your question, after this introduction: He (peace be upon him) said: . When the angel conveys to him: So-and-so prayed upon you or greeted you, Allah returns the soul to his body, and he returns the greeting. This is one of the special attributes of the Messenger. The prophets shared with the Messenger the preservation of their bodies, but Allah chose the Messenger by assigning an angel, or angels, to roam the world; whenever they hear someone praying upon the Messenger, saying "So-and-so prayed upon you," he returns the greeting and prays upon them.
So we can summarize the matter by saying that the Messenger (peace be upon him) is now living in the noblest barzakh life as the first reward for his jihad and his spreading of Islam, without a doubt. I mentioned earlier the martyrs and the righteous believers. The Messenger (peace be upon him) said regarding the martyrs: . So the bodies of the martyrs are in their graves, but their souls fly out and eat from the fruits of Paradise through what? These green birds. The souls of the martyrs are in their crops. Regarding the believers, he said: . So this is the bliss of the prophets, which will undoubtedly be nobler and higher than the bliss of what? The martyrs and the righteous believers. The meaning of all this is that there is a connection between the soul and the body for the prophets; because their bodies, as we mentioned, are alive, there is nothing strange in this, as long as his body is alive and his soul follows him, connected to him whenever Allah (Mighty and Majestic) wills, and the angels convey to him the news of those who pray upon him. So the matter has become clear, and praise be to Allah.