I think this is really common for teenage boys (owner of 3 of them).
I would keep the books, especially if there is stuff he liked when he was younger. My 14YO and 16YO have just revisited some series they enjoyed a few years ago. Re-reading is a great thing, and one day he might be so bored he will pick stuff off the shelf. It's a way of signalling that you are a household that values reading, and maybe he'll realise that he does too at some point.
Stuff that might work (but probably won't):
Bribery - 'I really think you would enjoy this and I will give you X if you read the first 100 pages'. Hey, it's worth a try.
Audiobooks - when exercising or as a family thing on car journeys. Or ebooks borrowed from the library. Somehow reading it on a screen feels less worthy to my boys and therefore more enticing.
Watching tv series based on books - one DS had read The Count of Monte Cristo and loved it so we introduced both to the French tv series on holiday when there was nothing else to do. The other DS will never read it but at least he has a little bit of knowledge of classic literature that he didn't have before.
Not sweating about them reading crap. It's a reading habit. Better Asterix and Tintin (obvs not crap) and graphic novels than nothing - and some crap is a lot better than you think.
Making sure they see their father read. My DH stopped reading fiction as a teenager but had to start again when he married me because I always had a book to read at bedtime. Now I look out for books he might like and get them from the library so he always has options, and the kids see him reading fiction.
Reading aloud to them. This was good for younger teens. We did Tom Sawyer when they were younger and To Kill a Mockingbird last year. I should try this again.
Borrow books for them from the library. I borrow a huge stack before we go on holiday for everyone in the house, and then if they don't enjoy them, I've not wasted any money.
Turn off the wifi at particular times, but especially if you're on holiday at some point during the day. Boredom may work.
None of these are great ideas, tbh, but if there were a reliable way of making teenage boys read, you would be doing it already, and so would all the English teachers and librarians in the land.
And yes, as adults some men do go back to reading.