My situation at home is similar to yours, OP. My son doesn’t read much either. His English however has been advanced so far, though I wonder if he’ll fall behind in high school. He’s two grade older than yours. What differs between yours and mine might be that my kid is talkative and listens to or watches people talking online a lot. Maybe a vocabulary building activity alone can help yours. But people are different, there are Albert Einsteins and there are Bill Clintons.