Nominalized verb and connection to noun after が particle

Question

I'm attempting to read a book and I don't understand the grammar 100% here.

ジャックはもうすぐ九歳。本を読んだり、自然を観察したりするのが大好きな男の子だ。

Overall, I believe it means:

Jack will soon be 9 years old. A lovable boy that reads and watches nature.

But, I don't understand why the second sentence does not end like:

本を読んだり、自然を観察したりする大好きな男の子だ。(No が particle at all

A lovable boy who reads and watches nature.

OR

大好きな男の子が本を読んだり、自然を観察したりする。(が particle moved to the front)

A lovable boy that reads and watches nature.

How does the grammar work on the second sentence here? I know that 本を読んだり、自然を観察したりする is being nominalized and then it becomes a noun, which makes it usable by が. But I do not understand how its connection with 大好きな男の子 works.

Answer 1

I think you've misunderstood the sentence because of the ambiguities in the form Aが好きなBだ.

For example,

犬が好きな人だ

can mean both that (I am) a person that likes dogs as well as (I am) a person that dogs like depending on the context (although I think it's most likely to be interpreted in the former way).

However,

寿司が好きな人だ

can only mean (I am) a person that likes sushi. After all, it would be completely ridiculous that sushi could have the willpower to like a person unless this was some weird science fiction.

Your example is similar to this latter example. It would be absurd if the act of reading books/watching nature could love a person.

Therefore, the only way the second sentence can be understood is as:

A boy that loves to read books and watch nature.