Haven't you taken classes on Classics or Philosophy? Try reading books relating to a historical period that interests you or from an author you talked about in school and you didn't find boring, or maybe books from a certain period or movement. For example, in the last period, I've been focusing on the first half of the 20th century and have been reading Fitzgerald, Waugh, Mitford. It's all connected so whenever you are interested in something of some cultural value you can find a wide literature behind it. And often a filmography too! If you are interested in politics, philosophy, law (court cases), mythology, epics, war, theatre, even love or (uncommon) poetry, ancient history/historiography and classical literature per se, then there are absolute masterpieces from Latin and Ancient Greek authors, it's a marvellous dimension to explore.
There are also essays or books relating to specific topics that you might find interesting, like the "Communist Manifesto" by Marx and Engels, Mill's "On Liberty", his partner's works on women's rights and, thinking about Mitford, on linguistics, though that's a rather silly piece of literature. I'm sorry I can't provide better guidance, school gave me much of my knowledge and the inputs/means to develop it further.
p.s Books aren't the only way, one can also learn from people and through dialogue! Try talking about this with him, maybe he has some useful tips!
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Μετά means "betweeen"/"after" in Ancient Greek, but the current meaning is quite different and there's a cool story behind. Andronicus of Rhodes had to catalogue Aristotle's works and didn't know how to deal with some unnamed notes. Since, in the order in which he received them, they occupied the position after the books on Physics, he simply decided to call them "τα μετά τα φυσικά" (metaphysics). The title was quite fortunate because the actual content of the book was metaphysics. Now, I'm being a bit paradoxical and paretymological, but basically, these notes were about "physics beyond physics". Nowadays "meta" has come to mean "something beyond/inside/of itself". Metablogging, for example, is to blog about blogging, metatheatre has various meanings, one is "to break the fourth wall" (beyond), metapoetry is "poetry about/of poetry".
Andronicus, who was in Rome, got those works from Athens after it was sieged by Sulla. Research on him would lead to talking about the civil wars which arose after his clashes with Marius and ended only with the Pax Augusta, defining a span of about 100 years that marked the historical and literary apex of Roman arts and of the drama not only of the Republic but of romanity lato sensu. More on topic, Horace wrote "Grecia capta ferum victorem cepit, et artes intulit agresti Latio" (Greece that was sieged in turn sieged its savage victor, and brought arts in rural Lazio). Under this perspective, Andronicus, himself of greek origins, and his aforementioned experience with Aristotle's works, are valid examples.
I quoted the word "paretymology", which is a false etymology (derivation of a word). One brilliant example is "Ita solus potitus imperio Romulus, condita urbs conditoris nomine appellata.", ending line of an initial chapter of the Ab Urbe Condita by Livius. Although he claims the contrary (for traditional fiction, not malevolence or ignorance), the name "Romulus" actually derived from "Rome", not the other way round. Another, more contemporary, case is the word "posh" (probably wrongly) thought to derive from "port out starboard home".