He might like the John D. MacDonald Travis McGee books too - another series I disposed of to make room for others, and regretted (I need a bigger house). I don’t remember any explicit sex scenes, but perhaps our Travis can tell you better if they are suitable for a 14-year-old boy (never having been one myself).
Those are too explicit - I read them in my teens. I checked out a “Dirk Pitt,” and I’ll have a look at it when I finish the Aeneid.
Jiohn D McDonald is a rather dark read, I thought. He and Len Deighton seem to have been through the same school of thought.
John D. Macdonald’s “Travis McGee” novels are perfectly appropriate for 14 year olds, but they might find the depictions of life in Florida in the 60s to 80s dated. No internet, cell phones, etc.