I agree about the preferences. I was always hyper-empathetic and hated nonfiction growing up. Now, I read it almost exclusively though usually in the context of auto/biographies ("The Road from Coorain") and books like "The Big Year" rather than straight-up just-the-facts books. For physics I loved the Dancing Wu-Li Masters and The Physics of Star Trek, more humanized versions of science-based books. Conversely, books that are too touchy-feely are now far too precious. I run screaming from any book that already has "poignant" somewhere on the jacket.
Oh, and chickens. I just read Storey's Poultry Encyclopedia cover to cover. (DD9 and I even found an incorrectly identified photo in there and need to contact the publisher.)
I think this really can be parent priorities. But even things I prioritize I don't push, even spending time outdoors. I just do it when I can, encourage them to do it. I was quite the homebody growing up, and I love spending time outdoors now. I hated school science, but I love it now and consider it an area that I have unschooled myself quite effectively.
I have a lot of beefs about my mother, but this I can say for her: she was never idle. Sure, she was fairly *sedentary* but those hands and that mind were always busy. If it wasn't a book, it was knitting or cross stitch or quilting. She would study favorite subjects, especially history, family genealogy. She was a talented artist (she wanted to study interior design or architecture in college but this was 1960 and she was soundly discouraged from all sides). She picked up scrimshaw when my parents were deep into their lapidary hobby. She picked up programming then desktop publishing and used her incredible skills to staff the Macintosh User Group office for years. She had a midlife career change from secretary work to more technology-based positions (this in the early '80s) and retired as a desktop publisher. I cannot ever remember her without something in her hands, and excepting a considerable amount of pulp fiction (she devoured books and I remember many wonderful trips to the bookstore), it was always something that was on the edge of what she knew. She taught me that life was about learning, always, always learning the next thing. Clearing out her "sewing" room was a monumental effort after my parents' deaths. She had begun making dolls (clothes, etc.), had extensive collection of painting tools, calligraphy tools, old drafting tools, quilting, lapidary equipment.... drawers and drawers shelves and shelves filled with stuff for making more stuff.... a lifetime of learning the next thing. The boxes and boxes and towers of books.
She never pushed me in anyway to match her skills or her priorities. She encouraged me, for sure. She loved the company, even if it was just me accompanying her to the fabric store to help pick out patterns and materials for clothes she wanted to make for me. She never balked when I chose theater as a major. When I was deep into my favorite band, she bought me records. She never batted .400, but she was enthusiastic about trying.
Anyway, I ramble terribly.
I can't say as a parent that I never say "now is the time to..." because I do have bedtime routines with stories that they can exchange for quiet time. And I can't say I never pick up books and materials that might stretch them in "my" direction a little. I know "My Side of the Mountain" has been borrowed from the library on many occasions and never read or requested. Oh well. Chronicles of Narnia sits on the shelf. They love the movies but somehow aren't interested in the books. The Cuisenaire rods get used for other purposes.
So, maybe you could find some science-based fiction to read, but if he's not interested... I think well rounded people are wonderful. I know in centuries past, it was the great goal for young gentleman to become well versed in all sorts of disciplines. But as far as parents creating well-roundedness rather than just providing the materials for children to choose, well, I think that's overrated.
Again and again, it all comes back to what is meaningful. Sure, we all have that novel or subject that some great teacher introduced us to and we are forever grateful. My mom handed me The Hobbit after we saw Ralph Bakshi's film of LOTR, beginning a lifetime love. But for the most part, I don't think these things can be designed in because you never know what is going to be the "hook". And, with school and all things that become essentially mandatory, how many things did I turn my back on vs. how many things that really inspired me? I mean, I love Wuthering Heights and all that, even if Heathcliff is a cruel, abusive bastard, but it was a small gift in a sea of trash.