:wasalamex
The trials a person faces in the grave are on the soul:
http://www.islamicboard.com/akhira-...akh-our-physical-world-seperate-distinct.html
The punishment in the hereafter however will be physical [i.e. in the hellfire/paradise the reward will be physical]
When a person dies, two angels will approach them [Munkar & Nakir] and ask them three questions:
Who is your Lord?
Who is your Prophet?
What was your religion?
We know that every prophet came to his people to call them to Islaam [submission to Allaah], so the answer to the first question would be that Allaah is our Lord, Islaam is our religion, and the prophet may differ according to each person. However, since Muhammad (peace be upon him) came for all of mankind, then anyone who is alive after him has to accept him and therefore answer: Muhammad (peace be upon him) as a response to the 2nd question. Whether they are a jew, christian, hindu or whatever, since this is the final Messenger Allaah sent to the world.
A person can only truelly answer these if they really obeyed the Messenger.
If the person was a sinner, they may get punished in their grave. However, this may be an expiation for them so they don't be punished in the hellfire. This is in regard to the believers. For the disbelievers - the end of this life is the beginning to an endless life of sorrow. We seek refuge in Allaah from that.
If the believer answered the questions correctly, then the angels will open a window in their graves. They will say that this is your place in the hellfire, but this is your place now in jannah [the gardens] since you obeyed the Messenger etc.
However, for the disbeliever - they will say that 'i heard the people say so and so, so i went along with it.' - they won't answer the questions properly because they were not true believers in this life, so the angels will open the window of paradise and say that this would have been your place in jannah, but this is your place in the fire. We seek refuge in Allaah from that.
The people in the graves will remain there for as long as Allaah wills, and then the our will be established. The graves will be overturned and some scholars say that a liquid will come down [like rain] - and we will grow back to life [like the plants do when rain is sent.]
On that day every person will be in a state of terror, except those who used to fear this day in this life.
It is) a Day whereon men will be like moths scattered about,
And the mountains will be like carded wool.
Then, he whose balance (of good deeds) will be (found) heavy,
Will be in a life of good pleasure and satisfaction.
But he whose balance (of good deeds) will be (found) light,-
Will have his home in a (bottomless) Pit.
And what will explain to thee what this is?
(It is) a Fire Blazing fiercely!
[Qur'an Surah Al Qaar'ia 101]
That Day shall a man flee from his own brother,
And from his mother and his father,
And from his wife and his children.
Each one of them, that Day, will have enough concern (of his own) to make him indifferent to the others.
Some faces that Day will be beaming,
Laughing, rejoicing.
And other faces that Day will be dust-stained,
Blackness will cover them:
Such will be the Rejecters of Allah, the doers of iniquity.
[Qur'an Abasa 80: 34-42]
The people of paradise however will unite with their families, those who joined them in faith.
They will recline (with ease) on Thrones (of dignity) arranged in ranks; and We shall join them to Companions, with beautiful big and lustrous eyes.
And those who believe and whose families follow them in Faith,- to them shall We join their families: Nor shall We deprive them (of the fruit) of aught of their works: (Yet) is each individual in pledge for his deeds.
[Qur'an Tur 52: 20-1]
If the people have proof from Qur'an or Sunnah that the people who pass away can meet each other within the graves, then please ask them to bring it forward. Allaah Almighty knows best.