The Looming Tower, by Lawrence Wright
https://www.amazon.com/Looming-Tower-Al-Qaeda-Road-11/dp/037541486X?dplnkId=8617e1e1-6559-4905-b764-20a05d24721a&nodl=1
I prefer books in this category written by journalists rather than by historians. But others prefer the opposite. It might be fun to get him one of each and see what he thinks/prefers.
I know you said non-fiction, but you might also want to consider contemporary spy novels (post-Cold War.) They may interest him, too. If you search the DCUM Book Club board, some threads should come up with different ideas (Re Russia, China, Iran etc.)