Books for his parents to read him or board books with one or two pictures per page for him to turn pages
Should be first on list. Look for the books that when you open, each page has a window/tab that you open that hides something.
Or just about any book of short stories Mom and Dad can read to him every night. My SIL and daughter does this every night. Grandson going on 3 years old in July and now able to pick some words out.