What is the religious ruling on a person who conspired against his relatives with criminals for money, and what is the ruling on his maternal uncles knowing about this without deterring him?

The Prophet (peace and blessings be upon him) explained that the inhabitants of Hell are five, and he mentioned among them the betrayer, and one who deceives people regarding their families and wealth, and whoever had two faces in this world will have two tongues of fire on the Day of Resurrection.

A Muslim must help his brother, even if he is a wrongdoer, by preventing him from committing injustice, and beware of those who cause discord.