How can she save her deceased grandfather from the sin of consuming other people’s wealth?
Question

                My grandfather has passed away. I love him a lot and I ask Allah to have mercy on him. He is my father’s father. After he died we saw him in many horrible dreams. Once we saw him burnt, and another time we saw him tossing and turning in the toilet, and so on. After searching we found out that he has taken a land that belongs to an orphan and built his house on it. This orphan does not know about this. But before he died he asked this orphan to forgive him and gave him 3000 Saudi Riyals without telling him what this money is for. He forgave him but until now he still does not know.  

My grandfather and his brother -who passed away as well- they did not give their sister and aunty their portion of the legacy. Their sisters died but they have daughters, and their aunty died but she has one son.  

The problem is not only this. My grandfathers’ sons refused to confess the others’ rights, saying that they will not give their lands to the people. Although they do not go to the village, as they live in the city, and these lands and homes became deserted. We -grandchildren- are confused. He is our grandfather, and we are the ones who see him in our dreams. Please advise me. My grandfather is in torment.
Praise be to Allah.
    Firstly: 

    One of the most serious sins with which a person may meet his 
    Lord on the Day of Resurrection is consuming people’s wealth unlawfully. It 
    is one of the major sins that doom a person and make his burden of sins 
    heavy on the Day of Resurrection, and it may lead him to Hell. We ask Allaah 
    to keep us safe and sound. 

    One of the gravest forms of wrongdoing and transgression is 
    consuming the wealth of weak people such as women and orphans, whom Allaah 
    has singled out for extra care and concern, and a sterner warning against 
    consuming their wealth, because the wrongdoers find it easier to take their 
    wealth because of their weak position. 

    When Allaah mentioned the shares of inheritance in Soorat 
    al-Nisa’, He also warned the one who transgresses against this shar’i 
    division of wealth. Allaah says (interpretation of the meaning):   

    “And whosoever disobeys Allaah and His Messenger (Muhammad
    صلى الله عليه وسلم), and transgresses 
    His limits, He will cast him into the Fire, to abide therein; and he shall 
    have a disgraceful torment”

    [al-Nisa’ 4:14]

    Allaah also listed consuming orphans’ wealth as a major sin. 

    Allaah says (interpretation of the meaning): 

    “And give unto orphans their property and do not exchange 
    (your) bad things for (their) good ones; and devour not their substance (by 
    adding it) to your substance. Surely, this is a great sin”

    [al-Nisa’ 4:2]

    And He says (interpretation of the meaning): 

    “Verily, those who unjustly eat up the property of 
    orphans, they eat up only fire into their bellies, and they will be burnt in 
    the blazing Fire!”

    [al-Nisa’ 4:10]

    Usurping land is a major sin and the punishment for it is 
    severe; the punishment becomes more severe if the land belonged to an 
    orphan. The Prophet  (peace and blessings of Allaah be upon him) said: 
    “Whoever seizes a handspan of land unlawfully, he will be encircled by it 
    down through seven earths on the Day of Resurrection.” Narrated by 
    al-Bukhaari (3198) and Muslim (1610). 

    It is strange indeed, by Allaah, to see someone who is keen 
    to offer prayers and do naafil acts of worship, but then you find that he 
    has fallen into sin by usurping people’s rights, and he has taken on burdens 
    that mountains could not bear on the Day of Resurrection. His prayer, 
    fasting and reading Qur’aan did not deter him from his greed and he did not 
    show mercy towards the weakness of women, children and orphans, so he 
    transgressed against the rights that Allaah has decreed for them, so after 
    that how could we hope for him to be saved. 

    Our sister, 

    We ask Allaah to reward you greatly for your keenness to save 
    your deceased grandfather from the punishment that you think is happening to 
    him, but we can do no more than remind you of the reality that Allaah has 
    stated in His Book, and that our Prophet  (peace and blessings of Allaah 
    be upon him) has stated, that usurping land and consuming people’s wealth 
    unlawfully, and transgressing against the shares of inheritance, are all 
    major sins, and if a man did not repent from them before he died (and 
    repentance includes restoring people’s rights to them), if he did not repent 
    then he is exposed to the punishment of Allaah. Then when the Day of 
    Resurrection comes, those who had rights will take them from his hasanaat 
    (good deeds) to an extent commensurate with their rights. If his hasanaat 
    are all used up, then some of their sayi’aat (bad deeds) will be taken and 
    added to his burden, then he will be thrown into the Fire, as the Prophet 
     (peace and blessings of Allaah be upon him) told us in his hadeeth 
    about the one who is bankrupt. Narrated by Muslim (2581). 

    Your grandfather’s repentance from usurping the orphan’s land 
    that you mentioned is not sufficient, rather he should have told him the 
    truth of the matter and given him his rights in full. 

    Al-Ghazaali (may Allaah have mercy on him) said concerning 
    the conditions of repentance from transgressions against people: 

    He has to tell (his victim) the extent of his wrongdoing 
    before asking for forgiveness, because asking for forgiveness for something 
    that the victim is unaware of is not sufficient. Perhaps if the victim 
    realizes the extent of his transgression, he will not feel at ease with 
    forgiving him and he will keep that until the Day of Resurrection and he 
    will settle the score by taking from his hasanaat or giving him some of his 
    sayi’aat. End quote. 

    Ihya’ ‘Uloom al-Deen (4/47). 

    Your grandfather has moved from the abode of action to the 
    abode of requital, so you cannot do anything for him except two things: 

    1 – Pray for him and ask that Allaah forgive him. 

    2 – Restore people’s rights to them and ask them to forgive 
    your grandfather. Restoring their rights to them – even if it does not 
    excuse your grandfather completely – will undoubtedly reduce a great deal of 
    the wrongdoing for which he is responsible. As you say that some of the 
    people whose rights were taken have died, then you must give their rights to 
    their heirs. 

    Secondly: 

    With regard to your paternal uncles, our advice to them is to 
    hasten to return people’s rights to them. If they do not do that, then they 
    will be usurping these rights, and they will meet Allaah with these major 
    sins if they do not repent from them. Their saying that they “will never 
    give their land to the people” is very strange, because they know that it is 
    not their land or their father’s land. What they should say, which is in 
    accordance with the truth, is “We will carry on usurping the people’s land”. 
    We would think that neither they nor all the Muslims would knowingly expose 
    themselves to the punishment of Allaah, for the punishment of Allaah is 
    severe, and all the pleasures of this world are as nothing compared to a 
    moment in the fire of Hell. We ask Allaah to keep us safe and sound.

    We ask Allaah to help your uncles to repent sincerely.

    And Allaah knows best.