Ruling on helping someone who has repented from riba-based transactions by paying off his loan
Question

                Is it permissible for me to pay off loans based on riba, as an act of charity to those who regret having gotten involved in interest? Or is it not permissible to pay off anything except the principal of the loan and not the riba?
Praise be to Allah.
    
    If a person has repented from riba-based transactions, has resolved not to 
    go back to them and regrets having done that, but he cannot avoid paying 
    this interest, because the system obliges him to pay off the loans with the 
    interest, otherwise he will be arrested and put in prison, then there is 
    nothing wrong with helping him to pay off this debt and the resulting 
    interest, and there is no sin on the one who helps him to do that, because 
    this is helping to relieve a Muslim of distress. 

    
    The Prophet (blessings and peace of Allah be upon him) said: Whoever 
    relieves a Muslim of distress, Allah will relieve him of distress on the Day 
    of Resurrection.

    
    Narrated by al-Bukhaari (2442) and Muslim (2580). 

    
    And because every time there is a delay in paying off the debt, the interest 
    accumulates further. 

    
    The scholars have stated that if a person who is in debt for something 
    haraam repents to Allah, there is nothing wrong with giving him zakaah funds 
    to pay off his debts. 

    
    Shaykh Muhammad ibn ‘Uthaymeen (may Allah have mercy on him) said: 

    
    Question: if a person is in debt for something haraam, can we give him 
    zakaah?

    
    Answer: If he has repented, we may give him, otherwise we do not give him,  
    because this comes under the heading of helping him with something haraam, 
    hence if we gave to him, he would take out another loan.

    
    End quote from ash-Sharh al-Mumti‘, 6/235 

    
    Dr. ‘Umar Sulaymaan al-Ashqar said: If a person has got into debt by way of 
    riba, it is not permissible to pay off his debt from zakaah funds allocated 
    for debtors, unless he has repented and given up dealing in riba.

    
    End quote from Abhaath al-Nadwah al-Khaamisah li Qadaayaa az-Zakaah al-Mu‘aasirah, 
    p.210 

    
    But in the case of one who has not repented from riba-based transactions, 
    and only wants to solve his problem, and if his debt was paid off, he would 
    not mind going back to dealing in riba again, then it is not permissible to 
    help such a person to pay off his debt, because that comes under the heading 
    of helping him in sin and transgression, which is not permissible. 

    
    And Allah knows best.