Yeah, talking about Disney's dinosaur book, I'm pretty sure you mean 'Dinosaurs Before Dark' from the Magic Tree House series, which is a Disney-owned property now? Or maybe 'The Good Dinosaur' tie-in? Honestly, either way, both are absolutely fine for young readers.
I've read the Magic Tree House one with my nephew who was around six, and he loved the adventure parts. The chapters are short, the language is simple, and it mixes facts with fantasy in a way that doesn't feel overwhelming. It never gets too scary, even with the T-Rex.
Some parents might worry about the fantasy elements, like the time travel, but I think it actually helps make the historical stuff more engaging. My nephew started asking about real dinosaurs after we finished it, so it works as a gateway.
Just keep in mind the reading level is maybe first or second grade, so an adult might need to read it aloud to a very young kid. That worked for us, anyway.