My ds just turned 18. He used to be an avid reader when he was younger but got out of the habit after primary school.
I'm biased but based on what others say too, he's funny, clever, and he also likes observing people and society.
Quite mature for his age so wants something for adults not YA fiction.
Definitely not scifi or fantasy as that's not his thing.
I'm thinking something along the lines of Martin Amis, Ian McEwan. I definitely think the Goldfinch by Donna Tartt would appeal but it is quite long for a first foray back into reading.
So, if he were to read one novel this summer to see if he can get back into reading what could it be?