Episode 5 goes deeper into her story, revealing that Kathleen's motivation for finding Henry is because he ratted out her brother to FEDRA, resulting in his death.

Source: https://www.cbr.com/the-last-of-us-twd-lesson/

Notably, one of the most important revelations in is that Sirius Black is an innocent man, and the real enemy who ratted out Harry's parents is Peter Pettigrew ( reveal this, but it does so rather chaotically.

Source: https://collider.com/prisoner-of-azkaban-best-directed-worst-written-harry-potter-movie/