Even after Eugene kills a man for Christopher, Tony will not let him leave, and after it is disclosed that Eugene is also reluctantly cooperating with the FBI, he decides his family's best interests are served by his death and proceeds to hang himself.
Tony will not let him leave. Eugene kills a man for Christopher. He decides. His family's best interests are served by his death and proceeds. This was to hang himself. Eugene is also reluctantly cooperating with the FBI. This was what it is disclosed.