Law & Order: Organized Crime season 4 will finally introduce Stabler's brothers. After an extended absence from the Law & Order franchise, Christopher Meloni returned to the role of Elliot Stabler for the spinoff Organized Crime. He made his return appearance as part of a crossover episode with SVU, which centered around Stabler as he dealt with the murder of his wife Kathy (Isabel Gillies). That arc served as the driving force of the show's first installment, though Organized Crime has since gone through several changes both on-camera and off, in terms of changing storylines and new showrunners.

https://screenrant.com/law-order-organized-crime-season-4-stablers-brothers-characters-update/