I'm realizing my formatting is not coherent. Apologies.

My question is: Is the usage of the word himself correct in the first paragraph? I suggested he correct it to the second option for his homework, but am still curious.

Who heard? "He" heard.

That's what my 5th grade English teacher would have said.

I think.

It's "he" but I like your rewrite much better.

Apparently grammar questions get me to delurk.

"He" (as other have pointed out) is correct. 'Himself' is a reflexive pronoun and is used only when the subject of a sentence is also the object of the verb, e.g. "He took a photo of himself".

In this instance, himself is an intensive pronoun requiring that the noun to which it refers is present in the same sentence. So, the original use is incorrect.

Yeah, the reflexive pronoun 'himself' is wrong here, and your rewrite is preferable.

To explain the discrepancy here, the lad used 'himself' as a reflexive in the subject when he would have to use it as an intensive. However, to use it as an intensive requires an antecedent.

Yes! I thought it was probably he. I really did but was still unsure.

I understand the definition of a reflexive pronoun now. Thanks for spelling it out for me. I needed that. :-)

You could also just correct it to "He and his mother, Bone, were listening to Ms. Merrion explain to the gardener that she did not want a dog."

But yeah, I agree that your "heard Mrs. Merrion" version is even clearer than "were listening to Mrs. Merrion explain..."

Easy way: "himself were[was] listening"

Does that sound right? No, thought not.

A similar thing came up in this whine about clunky English in US college students:

5. "Whomever" should be "whoever."
6. "Myself" should be "I."

Nos. 5 and 6 are examples of "hypercorrection": errors that are induced by a combination of grammatical confusion and a desire to sound fancy, such as the chorine who refers to "a girl like I." Her equivalent today would say "a girl like myself." The enormous popularity of that last word stems in part from understandable uncertainty over whether "I" or "me" is correct.

He also complains about an increase in the use of British spelling and expressions, which someone in the comments attributes to Harry Potter.

increase in the use of British spelling and expressions, which someone in the comments attributes to Harry Potter

Interesting - and I'd say maybe Harry Potter, but more likely Harry Potter is part of the larger phenomenon of much greater media trading between the UK and US over the last two decades.

My mom has spent her career in journalism and is a serious language-watcher, and she's been claiming to see "creeping Britishisms" for a long time now, even before the first HP book came out in 1997. She has some enjoyable standard Safire-like rails against the use of certain increasinly common Britishisms like saying someone "went missing," ("they didn't GO missing! They were going somewhere specific, and now they ARE missing!" agreeing to "get a coffee," and the like - she has more I can't recall just now.

I liked your rewrite better, but not because of 'himself' - because I read the original as:

"His mother, [whose name is] Bone, and [puppy 1]"

Your version makes it clearer to me that the listeners were Mom, puppy 1, and puppy 2.