There is a long, sad tradition of sons taking up the mantle of a famous parent's literary world. I know I've mentioned this before in regards to Todd McCaffrey and Felix Francis, so it's clear that I'm not a fan. Years ago I read the joint venture between Walter and Steven, and I wasn't impressed. I felt that the series was starting to veer into straight up fantasy instead of tales about a boy and the wild horse that loves him. I don't know why I thought this would be any closer to the heart of the series than that joint book was, because it's obvious that, without his father's input, Steven Farley has completely lost sight of who and what the Black Stallion is and what role his relationship with Alec means to the books.
Let's be clear, this is not a book about the Black Stallion. This is a book about an aging racehorse that happens to share the name with the Black and happens to run races with someone named Alec as his jockey. This pair ends up in Ireland after experiencing an eerie incident involving a lost girl and a horse - which never gets resolved, by the way - where the horse ends up lame. They then go to a farm to recover, where a bunch of stuff happens to someone else while Alec wanders around doing absolutely NOTHING. Then there's a bit of nonsense and it's over.
This kid, who is not the Alec Ramsey we know and love, does nothing active, makes no choices, displays little sense, and is incidental to the story as a whole. Meanwhile, the "Black" also does nothing, including show any spark of spirit or intelligence, acting more like an aging cart horse than the Black. As for Henry, he gets conveniently, and oddly, shuffled offstage at the earliest opportunity.
Is this a good book? Not really. It's adequate for a horse tale, if you don't mind a story told from the wrong POV. The entire story would have been much more effective from Mora's side of things.
Is this a Black Stallion book? Emphatically not! Not only does the Black not act like himself, neither does Alec. Not to mention, the story isn't about them and they are only in the story to sell the book.
Reread any of Walter Farley's books instead, his worst writing is better than his son's best.