He returns in the series finale, along with Fiona and Lip where they arrive for the birth of their new brother Ben. He tries to plead with Lip on not letting Fiona go with her choice of taking the kids Stella and Ben, since he was closest to Frank. At the end, Carl gets through to his brother and watched Lip plead to Fiona because turned out fine with or without their parents. He watches Fiona hand Frank money to leave however, the latter refused to take it as Carl sees that he couldn't live without his family and is pleased to see this side. In the end, he makes amends with his family and partakes in their activities.