What is the ruling on delaying the repayment of a deceased father's debt, given that the son spent a portion of the money designated for repaying the debt on his marriage, then repaid the debt later, and he has been providing for his siblings since the father's death?

The repayment of a deceased person's debt from what they left behind must be expedited, according to the hadith: "The soul of a believer remains suspended by their debt until it is repaid." Therefore, the sin falls upon whoever delays the repayment if the deceased left wealth. As for the deceased, there is no sin upon them if they were not procrastinating during their lifetime. You must repent and seek forgiveness for using what your father left in an improper manner, and increase in supererogatory acts of worship and good deeds.