it sounds as if you;re doing this already, encouraging his love of learning. I think I remember your son is quite young still, so I wouldn’t worry too much. Reading stories is the best you can do i think. It reinforces the message that books are fun and reading is good, without it being hard work for him. I think until children are about 8 ish (very big generalisation, based on one of my own daughters) reading by themselves can be hard work, like us trying to read a book in a foreign language that we did at school. You can do it, you can work it out, but it’s work, not pleasure. By reading books to him, you make books, stories and reading fun, and then when his reading is more embedded, he’ll start to take more interest. For some children reading stories will never be interesting enough as an activity, but perhaps a non-fiction book can suddenly make it ‘necessary’ for them to read. Or a website.
If he needs to read books at home as part of homework, perhaps you can make it a game. Alternate a sentence, or a page. You read one, he reads one. Lightens the load and moves the story forward to keep it interesting, and he’s still reading. Word games? Lots online, depending on what he’s doing in school right now.
But most of all, I think you’re already doing the right thing: reading him lots of books which he loves. the rest will all fall into place when his brain is ready for it.