Henry revealed the location of the leader of the Kansas City resistance and Kathleen’s brother, Michael, to the oppressive organization FEDRA. This, unfortunately, resulted in Michael’s untimely death.
As a result, Kathleen could not forgive Henry and spent the rest of her short-lived life hunting him down mercilessly.
However, Henry, who is played by Lamar Johnson in the show, collaborated with FEDRA in order to save his younger brother.
Sam, who is incredibly reliant on his older brother, has Leukemia. FEDRA promised Henry the cure if he told them where Michael was, which left him with no choice.
So, Henry ultimately is the cause of Kathleen’s brother’s death, which is deeply upsetting for both him and Kathleen. It is also what eventually seals both Henry and Sam’s fate in The Last of Us.

What Is a Collaborator in The Last of Us TV Show?
A collaborator is someone who worked with the oppressive organization FEDRA to find rebels and criminals. Usually, the criminals would then be punished by death.
Typically, collaborators are civilians that are hard done by or in a tough spot and are given what they need in exchange for information on high-profile rebel targets wanted by FEDRA.
In The Last of Us TV show, Henry tells Joel that he was a collaborator for the Kansas City FEDRA and helped them find the resistance leader in exchange for medicine for his brother Sam.
However, Henry isn’t alone, as there were multiple civilians who collaborated with FEDRA against the resistance. Unfortunately, they are all killed at the beginning of episode 5.
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