syntactic analysis - Using "it" after a comma to restate a previously-defined concept within the same sentence

I hope I'm posting this in the correct forum. If not, please direct me to the proper place to move my question. This is my first time using this site since I found it on Google, though I've used some of the answers here as references a number of times before, so please bear with me.

I'm in the process of editing a friend's story, as she is unfamiliar with a lot of grammar and punctuation rules. I've been trying to explain to her why I'm making each edit as I go so that she can learn from the experience.

I've run into a chapter where she's used a similar sentence structure a few times, and I'm not positive that it's incorrect, as I've seen it done plenty of times before, but it just feels wrong to me. If it is incorrect, can you tell me how to explain it to her grammatically so she's less likely to make the same mistake again?

Here are the examples:

• The thought that his kind were something to fear or at least be wary of, it was harmful.




• The way Jordan was smiling and the lightness in his voice, it was unlike the man he had seen before.




• The memory of her face, caught contorted in the middle of a scream, it had haunted him for the first year.

To me it feels like it would be better to remove the ", it" in each case but I don't want to tell her something is incorrect if it works grammatically (though I might mention that it feels more natural without that). If I'm analyzing the sentence structure properly, it seems that the "it" she's using is just simplifying and restating the noun used at the beginning of the sentence, before the comma break ("the thought," "the way," "the memory"), but could using "it" in that manner also apply to other parts of speech that I should warn her about?

Also, are there instances where, with certain formatting changes, the "it" can properly repeat the subject without being grammatically incorrect? For example, I've seen situations where someone would use an ellipsis in place of a comma, but I'm not sure if they mean to trail off and then begin a new sentence with it, or what.

Sorry for the long-winded question. I'd appreciate any answers you may have for me.

Answer

The three sentences use it in different ways.

The thought that his kind were something to fear or at least be wary of, it was harmful.

Although the sentence could dispense with it without significant change in meaning, the pronoun changes the way the idea is conveyed in the sentence (emphasizing the subject, as @pablopaul already noted). Compare:

"The thought that his kind were something to fear or at least be wary of -- it was harmful."

The way Jordan was smiling and the lightness in his voice, it was unlike the man he had seen before.

The it seems more like a "dummy it" (not a useless it) in this case.

The memory of her face, caught contorted in the middle of a scream, it had haunted him for the first year.

I see no useful purpose served by it here.

In general, these examples also suggest a possible carry-over from the writer's native idiom (possibly a non-native speaker of English).