How All This Started Book

I'm not sure what write about this book. I consider it to have some major flaws and problems as a novel, but nevertheless, it was a page-turner.
It's a coming-of-age story, (presumably set in the 90s, though we're never told this) about a Texas teenager, Austin, and his volatile older sister, Abilene. Her own baseball career was arrested because of her gender, but she's determined to make him the next Nolan Ryan. But she has overwhelming personal problems of her own, which soon become apparent.
I think the problem with this book is that it's so focused on a handful of themes that it ignores questions the reader may want to know. For example, what does the father do for a living? Abilene isn't gainfully employed most of the time, but always seems to have gas for her vehicle, and money for whatever other things she needs or wants. Why are the kids so contemptuous of the parents and the small town they live in? Why does Abilene blame the parents for her mental illness? The mother is never really fleshed out as a person, but is mostly a generic "mother" figure. The novel seems to endlessly repeat certain themes, while ignoring other content that's needed to make it seem complete.