Some things are just boring. How to make accounting interesting? Unless Hooters girls are the teachers, you just can't. It is pretty much the same with trading. I saw a woman teaching trading on tradingschools.org, (forgot her name) and although the material was nothing special at least she got 5 stars on entertaining value. Or you can put real money right away at stake and it get interesting really fast!
I remember the very first trading book (best trading book ever for beginners btw) that I've read. This was a time before I even knew a site like ET existed. I was around your age at 19 or 20. I read the whole book (300 pages) in one night. It was that interesting. You seriously have some trouble with focus if you have trouble reading a book and it is not a good indicator of success. And books are on average $10 each.
I must admit this was my own instinctive feeling, too, on first reading the OP. (I also suspect that "how to make it less boring" may, at least to some extent, be a misguided question, in the sense that from my own experience, the most boring, tedious and difficult-to-get-through ones have actually been of the most benefit to me, overall.) Not my experience at all, there: I'd say my average spend per trading book has probably been around $60-$70. And one of the most helpful ones, for me, was about $150, as I remember (privately published). Out of perhaps 100 textbooks I've read since I started reading about trading, I'd say there were probably about 10-12 of them that were really majorly helpful and productive for me, and then perhaps about 10-12 more that taught me something, provided some value, and that my trading's probably slightly better for having read than it would be if I'd never seen them. All the rest were more or less a waste of time. I don't think such that's a bad "win-rate", though, overall. It's certainly true, however, that hard copies are much more productive and worthwhile than digital ones, for some people (of whom I'm one, myself).
At 19, it's highly doubtful that he has the necessary critical thinking skills do do all that. What he needs to do is go to college and major in something technical. That will at least help him build up those skills and at the same time give him a backup plan.
Try different books. try reading hard copy. If you still find reading it boring, I'm afraid you have to try different career.
For me, the best books I read were all under $20. Most of them were "classic" I think. I might have brought a few in the $40-$50 range, but they were bad. And yes, hard copy are better then digital. With hard copies you can write notes and scribble in them. Use a highlighter and stuff. If the OP has any creative thought he might had came up with the idea to PRINT the digital copy he has on paper. Seriously, some of the questions people ask...
I would think the reward for learning to trade well, (that is, being able to plop yourself down in front of a computer anywhere and be able to make significant money for the rest of your life) would be motivation enough to keep the learning "interesting".
OP should read Reminiscences... and maybe he gets the trading bug. After that any trading book will be interesting.
Start with the original Market Wizards, each interview is self contained, the shortest is only a few pages long. You can skip any you find boring.
The edges the "wizards" once enjoyed are long gone. But the Schwager books still have entertainment value.