This is a good kid adventure, I like the setting and characters, and just enough is explained to keep the reader engaged.
I do have some concerns, though, with how it's currently written:
The biggest concern is that Liam never seems to know why he's doing anything. He shows flashes of bravery, but never seems to make any substantial decisions other than bolting from Wesley. In particular, the pivotal encounter ends with the protagonist being rescued by Tom in a way that Liam had no hand in preparing. (I mean, Liam should
have asked Tom and the Lady for the gold directly, but it's understandable that it doesn't occur to him.) Liam was willing to trade his benefactor Lady's only protection directly to the one who seemed to want to do her harm
... this is a good lowest-of-the-low-point for a hero to have, but he should at least feel bad about it.
Liam's definitely "grown a pair" by the time he faces his father again, but that could just be "I lived through worse than you" bravado rather than the kind of maturity you probably want to portray.
Giving Liam a hand in determining his fate will also remove any cynic's interpretation that Liam isn't even brave... he's just desensitized.
I'm not saying that Liam has to figure everything out half-way through the story, but he can't be an ignorant babe the whole way through either. One of the most memorable lines from The Tenth Kingdom
was when Tony responds to his assigned quest by yelling at the Blind Woodsman "What is it with you people?!"
Though you'll find plenty of stuff describing the Three Act Structure, and that's good for the broad timing of major events, but I'd recommend looking at the Monomyth for deciding what Liam does and in what order. You don't need to invent a new story structure from whole cloth. This is a solo adventure, and the Monomyth is a proven formula for solo adventures.
On pages 13-15, it might make sense to put GRANDAD'S CAR in the scene headers to eliminate any confusion with the parents' car.
On page 29, removing "It's gone." might make it easier to understand.
Tom is not introduced properly. I have no idea how old he is, what he looks like, or what he's wearing. But he has an intimidating bell.
The pirates came pretty much from nowhere. And if they justify their actions by saying they're pirates, then they pretty much are Johnny Depp pirates
Missing character line on page 57, though I guess it was Luis.
On page 66, Liam is referred to as Tom a couple times.
The ransom on the ruby seems to change from 100 gold pieces to 10.
Overall, a great story! Keep up the good work!