Salam
@MyM
The Quran talks about intercession through out.
If intercession to Rasool (s) is not shirk during his life, but praised, then him passing away would not raise him into a station that is worshipped either if we talk to him. This unless, you say the position of hearing us from unseen would make him on par with God.
This is from a Quranic perspective, God warning us of hypocrites mentions:
وَإِذَا قِيلَ لَهُمْ تَعَالَوْا يَسْتَغْفِرْ لَكُمْ رَسُولُ اللَّهِ لَوَّوْا رُءُوسَهُمْ وَرَأَيْتَهُمْ يَصُدُّونَ وَهُمْ مُسْتَكْبِرُونَ | When they are told, ‘Come, that Allah’s Messenger may plead for forgiveness for you,’ they twist their heads, and you see them turn away disdainfully. | Al-Munaafiqoon : 5
It's convenient now to make an excuse and say he is dead, so we can't seek his intercession and come to him that he asks forgiveness for us! I will deal with the dead issue later in the post.
وَمَا أَرْسَلْنَا مِنْ رَسُولٍ إِلَّا لِيُطَاعَ بِإِذْنِ اللَّهِ ۚ وَلَوْ أَنَّهُمْ إِذْ ظَلَمُوا أَنْفُسَهُمْ جَاءُوكَ فَاسْتَغْفَرُوا اللَّهَ وَاسْتَغْفَرَ لَهُمُ الرَّسُولُ لَوَجَدُوا اللَّهَ تَوَّابًا رَحِيمًا | We did not send any apostle but to be obeyed by Allah’s leave. Had they, when they wronged themselves, come to you and pleaded to Allah for forgiveness, and the Messenger had pleaded for them [to Allah]for forgiveness, they would have surely found Allah all-clement, all-merciful. | An-Nisaa : 64
وَمِنَ الْأَعْرَابِ مَنْ يُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الْآخِرِ وَيَتَّخِذُ مَا يُنْفِقُ قُرُبَاتٍ عِنْدَ اللَّهِ وَصَلَوَاتِ الرَّسُولِ ۚ أَلَا إِنَّهَا قُرْبَةٌ لَهُمْ ۚ سَيُدْخِلُهُمُ اللَّهُ فِي رَحْمَتِهِ ۗ إِنَّ اللَّهَ غَفُورٌ رَحِيمٌ | Yet among the Bedouins are [also] those who believe in Allah and the Last Day, and regard what they spend as [a means of attaining] nearness to Allah and the blessings of the Messenger. Now, it shall indeed bring them nearness, and Allah will admit them into His mercy. Indeed Allah is all-forgiving, all-merciful. | At-Tawba : 99
خُذْ مِنْ أَمْوَالِهِمْ صَدَقَةً تُطَهِّرُهُمْ وَتُزَكِّيهِمْ بِهَا وَصَلِّ عَلَيْهِمْ ۖ إِنَّ صَلَاتَكَ سَكَنٌ لَهُمْ ۗ وَاللَّهُ سَمِيعٌ عَلِيمٌ | Take charity from their possessions to cleanse them and purify them thereby, and bless them. Indeed your blessing is a comfort to them, and Allah is all-hearing, all-knowing. | At-Tawba : 103
Now comes the issue, how does Rasool (s) hear us, the Quran talks about him as a witness to our deeds:
يَعْتَذِرُونَ إِلَيْكُمْ إِذَا رَجَعْتُمْ إِلَيْهِمْ ۚ قُلْ لَا تَعْتَذِرُوا لَنْ نُؤْمِنَ لَكُمْ قَدْ نَبَّأَنَا اللَّهُ مِنْ أَخْبَارِكُمْ ۚ وَسَيَرَى اللَّهُ عَمَلَكُمْ وَرَسُولُهُ ثُمَّ تُرَدُّونَ إِلَىٰ عَالِمِ الْغَيْبِ وَالشَّهَادَةِ فَيُنَبِّئُكُمْ بِمَا كُنْتُمْ تَعْمَلُونَ | They will offer you excuses when you return to them. Say, ‘Do not make excuses; we will never believe you. Allah has informed us of your state of affairs. Allah and His Messenger will observe your conduct, then you will be returned to the Knower of the sensible and the Unseen, and He will inform you concerning what you used to do.’ | At-Tawba : 94
Now the issue comes, did this role stop after his death?
The Quran through a series of verses:
فَإِنْ كُنْتَ فِي شَكٍّ مِمَّا أَنْزَلْنَا إِلَيْكَ فَاسْأَلِ الَّذِينَ يَقْرَءُونَ الْكِتَابَ مِنْ قَبْلِكَ ۚ لَقَدْ جَاءَكَ الْحَقُّ مِنْ رَبِّكَ فَلَا تَكُونَنَّ مِنَ الْمُمْتَرِينَ | So if you are in doubt about what We have sent down to you, ask those who recite the Book [revealed] before you. The truth has certainly come to you from your Lord; so do not be among the skeptics. | Yunus : 94
Those who recite the book we will see are not ahlul-Kitab but the Messengers, the Quran also says:
وَاسْأَلْ مَنْ أَرْسَلْنَا مِنْ قَبْلِكَ مِنْ رُسُلِنَا أَجَعَلْنَا مِنْ دُونِ الرَّحْمَٰنِ آلِهَةً يُعْبَدُونَ | Ask those of Our Messengers We have sent before you: Did We set up any gods to be worshipped besides the All-beneficent? | Az-Zukhruf : 45
This is important, because it says he can ask of the Messengers God sent, and it's particularly Musa and his successors, and the proof of that is, if Mohammad (s) was ignorant, he would be required to seek the family of the reminder in terms of miracles and clarification:
وَمَا أَرْسَلْنَا قَبْلَكَ إِلَّا رِجَالًا نُوحِي إِلَيْهِمْ ۖ فَاسْأَلُوا أَهْلَ الذِّكْرِ إِنْ كُنْتُمْ لَا تَعْلَمُونَ | We did not send [any apostles] before you except as men to whom We revealed therefore Ask the family of the Reminder if you do not know. | Al-Anbiyaa : 7
The ask Messengers before you shows if Mohammad (s) was in doubt of Tawhid, he can simply get in contact and know the Messengers before him, this is rhetorical, saying Messengers of the past would all confirm tawhid, and not just that, but people if they get contact spiritually with Messengers, they would lead them to the current Guides of the times and confirm Mohammad (s).
The family of the reminder is Mohammad's (s) family, but if it wasn't him who was the last reminder of the time, and him and his people were ignorant, Quran is saying then in this case, they would be required to seek the family of the reminder which would be Moses and Aaron and their holy family. If it was wrong to talk to the Messengers of the past, the rhetorical command would not make sense.
More is to be said, the Quran talking of the sky reality:
وَإِنْ كَانَ كَبُرَ عَلَيْكَ إِعْرَاضُهُمْ فَإِنِ اسْتَطَعْتَ أَنْ تَبْتَغِيَ نَفَقًا فِي الْأَرْضِ أَوْ سُلَّمًا فِي السَّمَاءِ فَتَأْتِيَهُمْ بِآيَةٍ ۚ وَلَوْ شَاءَ اللَّهُ لَجَمَعَهُمْ عَلَى الْهُدَىٰ ۚ فَلَا تَكُونَنَّ مِنَ الْجَاهِلِينَ | And should their aversion be hard on you, find, if you can, a tunnel into the ground, or a ladder into sky, that you may bring them a sign. Had Allah wished, He would have brought them together on guidance. So do not be one of the ignorant. | Al-An'aam : 35
This shows if Mohammad (s) can connect people to this reality, he would, but it's not his fault people turn away.
Surah Hijr expands on why he doesn't connect them:
وَلَوْ فَتَحْنَا عَلَيْهِمْ بَابًا مِنَ السَّمَاءِ فَظَلُّوا فِيهِ يَعْرُجُونَ | Were We to open for them a gate of the sky, so that they could go on ascending through it, | Al-Hijr : 14
لَقَالُوا إِنَّمَا سُكِّرَتْ أَبْصَارُنَا بَلْ نَحْنُ قَوْمٌ مَسْحُورُونَ | they would surely say, ‘Indeed a spell has been cast on our eyes; indeed, we are a bewitched lot.’ | Al-Hijr : 15
وَلَقَدْ جَعَلْنَا فِي السَّمَاءِ بُرُوجًا وَزَيَّنَّاهَا لِلنَّاظِرِينَ | Certainly We have made mansions in the sky and adorned them for the onlookers, | Al-Hijr : 16
وَحَفِظْنَاهَا مِنْ كُلِّ شَيْطَانٍ رَجِيمٍ | and We have guarded it from every outcast Satan, | Al-Hijr : 17
إِلَّا مَنِ اسْتَرَقَ السَّمْعَ فَأَتْبَعَهُ شِهَابٌ مُبِينٌ | except someone who may eavesdrop, whereat there pursues him a manifest flame. | Al-Hijr : 18
There are many verses that show the position of the great stars in the sky in this world. This means they are spiritually connected and meant to be seen.
The parable of light also describes the light to be found in houses God permitted to be risen and his name remembered in, and these are the households chosen of the past till now.
Likewise, the Ahlulbayt of Ayub (a) was with him in moments of trial and the likes of them also with him (past Ahlulbayts).
In Jesus time, it WAS the only way to get to heaven. You HAD to believe in him. His message. 
