Because You’ll Never Meet Me by Leah Thomas

Ollie and Moritz are best friends, but they can never meet. Ollie is allergic to electricity. Contact with it causes debilitating seizures. Moritz’s weak heart is kept pumping by an electronic pacemaker. If they ever did meet, Ollie would seize. But Moritz would die without his pacemaker. Both hermits from society, the boys develop a fierce bond through letters that become a lifeline during dark times—as Ollie loses his only friend, Liz, to the normalcy of high school and Moritz deals with a bully set on destroying him.