If the matter is as you have mentioned, you have committed a great sin, because you gave
false testimony and dared to swear falsely by Allah as well as cheating the judge and the ruler, not to mention helping in unjustly taking people's money. All these are major sins. You are not excused because you feared that the family may have been deprived of their father's pension, for Allah is kinder and more tender to this family (Part No. 23; Page No. 513) than you are. Allah (Exalted be He) states:
O you who believe! Stand out firmly for justice, as witnesses to Allâh, even though it be against yourselves, or your parents, or your kin, be he rich or poor, Allâh is a Better Protector to both (than you). So follow not the lusts (of your hearts), lest you avoid justice; and if you distort your witness or refuse to give it, verily, Allâh is Ever Well-Acquainted with what you do.
And He (Glorified be He) states:
And protect your oaths (i.e. do not swear much).
The Prophet also (peace be upon him) forbade perjury,
Should I inform you of the greatest major sin? They said: Yes, O Allah's Messenger! He said: To associate others in worship with Allah and to be undutiful to one's parents. The Prophet (peace be upon him) then sat up after he had been reclining (on a pillow) and said: And I warn you against giving a false testimony, and he kept on saying that warning till we thought he would not stop.
It has been authentically narrated on the authority of
`Abdullah ibn `Amr (may Allah be pleased with them) that he said:
A Bedouin came to the Prophet (peace be upon him) and said, “O Allah's Messenger! What are the most grievous sins?” ... I said, "What is an 'Al-Ghamus oath (false oath taken upon giving false and misleading testimony)'?” The Prophet (peace be upon him) said, "It is the false thereby a liar deprives a Muslim of his property unjustly."
As such, you must repent to Allah and ask His forgiveness for (Part No. 23; Page No. 514) the crimes you committed.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.