Just share with you my opinion.
Help is a causative verb.
Some special verbs are classified as causative verbs which are used to mean the subject orders the object to do something.
When you learn such verbs from grammar books, there are four verbs which are especially emphasized. They are "let" "make" "have" "help".
The feature of the four verbs is there is no "to" connecting a second verb which is still in its original form.
For example, I have my brother take out the garbage.
As for example two, according to grammar books, "help" is acceptable with "to" behind connecting another verb. Although I'm not a native speaker, I think adding "to" is acceptable is because that's how many people use it as the same as "help" in example one. How native speakers use their language (although sometimes may be inexplicable) is always no reason. Language-using,I think no matter what language, tends to be clear but concise, so I think that’s why more and more people use it without “to”. I hope it helps.
An English major.
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