Can Prophet Muhammad Hear Us?
Question

Some people believe that the Prophet Muhammad [(peace and blessings of Allah be upon him)] is "Shaheed" and is in BArzakh where he can hear us if we send 'durood' on him and also if we ask his 'wasta' [by virtue of his closeness to Allah] in praying to God.
Praise be to Allah.Is Prophet Muhammad alive?
The Prophet (peace and blessings of Allah be upon him) is alive in his grave in the sense of the life of Al-Barzakh , so he enjoys the blessings that Allah has prepared for him as a reward for his great good actions that he did in this world. But the life in the grave is not like the life of this world, or the life in the Hereafter. Rather it is the life of Al-Barzakh which comes in between his life in this world and his life in the Hereafter. Hence we know that he died as other Prophets and other people before him died. Allah says (interpretation of the meaning): 
“And We granted not to any human being immortality before you (O Muhammad); then if you die, would they live forever?” [Al-Anbiya’ 21:34] 
“Whatsoever is on it (the earth) will perish. And the Face of your Lord full of Majesty and Honour will remain forever.” [Ar-Rahman 55:26,27]
“Verily, you (O Muhammad) will die, and verily, they (too) will die.” [Az-Zumar 39:30]
And there are other verses which also indicate that Allah caused him to die. Moreover, the Companions (may Allah be pleased with them) washed him, shrouded him, offered the funeral prayer for him and buried him; if he had been alive in the worldly sense, they would not have done the same as is done for others who die. 
Fatimah (may Allah be pleased with her) asked Abu Bakr (may Allah be pleased with him) for her inheritance from her father (peace and blessings of Allah be upon him) because she was convinced that he had died, and no one among the Companions (may Allah be pleased with them) differed with her concerning that. Rather Abu Bakr (may Allah be pleased with him) responded to her request by saying that nothing could be inherited from the Prophets.  
The Companions agreed unanimously to choose a caliph for the Muslims to succeed the Prophet (peace and blessings of Allah be upon him), and that was done with the appointment of Abu Bakr (may Allah be pleased with him) as a caliph. If the Prophet (peace and blessings of Allah be upon him) had been alive in a worldly sense, they would not have done that. So this indicates that there was consensus among them that he had indeed died. 
When the tribulations (Fitan) and problems increased during the time of `Uthman and `Ali (may Allah be pleased with them both), and before and after that, they did not go to his grave to consult him or ask him for a way out of those tribulations and problems, or the way to solve them. If he had been alive in a worldly sense, they would not have overlooked that when they were in such great need of someone to save them from the trials that surrounded them.  
With regard to the soul of the Prophet (peace and blessings of Allah be upon him), it is in the highest part of `Illiyyin, because he is the best of creation, and because Allah has given him Al-Wasilah which is the highest position in Paradise. 
The life of Al-Barzakh is a special life. The Prophets and the martyrs are alive in Al-Barzakh as the Prophet (peace and blessings of Allah be upon him) said: “The Prophets are alive and they pray in their graves.” (Narrated by Al-Mundhiri and Al-Bayhaqi who classed it as authentic because of corroborating reports in Al-Bukhari and Muslim.) 
Allah Says (interpretation of the meaning): 
“And say not of those who are killed in the way of Allah, `They are dead.’ Nay, they are living, but you perceive (it) not.” [Al-Baqarah 2:154]
This is a special life, the nature of which is known to Allah. It is not like the life of this world in which the soul remains with the body.  
Can Prophet Muhammad hear us?
The basic principle concerning the dead is that they do not hear the words of the living sons of Adam, because Allah says (interpretation of the meaning): 
“but you cannot make hear those who are in graves.” [Fatir 35:22]
Allah confirmed that those whom he (the Prophet (peace and blessings of Allah be upon him)) was calling to Islam could not hear, by likening them to the dead. There is nothing in the Quran or in the authentic Sunnah to indicate that the Prophet (peace and blessings of Allah be upon him) can hear every Du`a or call from human beings. Rather it is proven that the only thing that reaches him (peace and blessings of Allah be upon him) is the blessings and Salams of those who send blessings and Salams upon him . 
This was narrated by Abu Dawud, 2041, with a sound chain of transmission from Abu Hurayrah (may Allah be pleased with him) who said that the Prophet (peace and blessings of Allah be upon him) said: “There is no one who sends Salams upon me but Allah will restore to me my soul so that I may return his Salams.” This does not mean that he hears the words of the one who sends Salams. Rather it is possible that he comes to know of those Salams when the angels convey that to him. If we assume that he hears the words of the one who sends Salams, this is an exception from the general rule, as in the case of the dead hearing the footsteps of those who carry his bier, and as in the case of the slain disbelievers in the well at Badr who heard the call of the Messenger of Allah (peace and blessings of Allah be upon him) when he said to them: “Have you found your Lord’s promise to be true? For we have found our Lord’s promise to be true.” (See Fatawa Al-Lajnah Ad-Da’imah, 1/313, 318, 321) 
Is calling upon Prophet Muhammad permissible?
With regard to calling upon the Prophet (peace and blessings of Allah be upon him) and asking him directly, this is the essence of polytheism which the Prophet (peace and blessings of Allah be upon him) was sent to forbid and to fight against its people. 
For more details, please see the following answers: 111019 , 10289 , 11402 , and 1439 . 
We ask Allah to bring the Muslims back to the right path. And Allah knows best. May Allah send blessings and peace upon his Prophet Muhammad and his family and Companions.
And Allah knows best.