Because You'll Never Meet Me by Leah Thomas
Ollie, who has seizures when near electricity, lives in a backwoods cabin with his mother and rarely sees other people, and Moritz, born with no eyes and a heart defect that requires a pacemaker, is bullied at his high school, but when a physician that knows both suggests that they begin corresponding, they form a strong bond that may get them through dark times.
Review from School Library Journal:
Ollie and Moritz are at the center of a unique and oddly compelling friendship in this epistolary debut. Ollie has a form of epilepsy that renders him "allergic to electricity," while Moritz, born without eyes, has a pacemaker to help control his cardiomyopathy. Both boys live in reclusive isolation, but when they begin to exchange letters, they find an unexpected opportunity to share their hopes, challenges, sorrows, and the tragic secrets that unite them. Ollie and Moritz are memorable characters with engaging and often humorous voices, and the dual narration creates tension as they reveal more of their lives to one another—including their struggles with loneliness, self-acceptance, brutal tormentors, first love, and the weight of the past. The story flirts with several genres before settling into science fiction by its close. Coupled with the questionable reliability of its narrators, this lends it a quirky, almost whimsical feel even as Thomas grounds it in heartfelt and often painful emotion.