books for a 15 year old boy with a mild learning disability ?

my younger brother is recently diagnosed with a mild learning disability that affects his ability to comprehend material he is reading or hearing. it affects him in all school subjects. not dyslexia btw. as a result he is struggling in high school and has low self esteem pertaining to his intelligence and capabilities. i was wondering if there are any books out there that would be easily accessible to someone with a mild learning disability, would help a high schooler’s self esteem, and would show him that reading/learning isn’t so scary, it can actually be fun! any help at all would be greatly appreciated. a couple facts about him is that he loves baseball and pop culture. i would say his reading level is around 6th-8th grade level. thank you so much for taking the time to read this post !