Lev

If this were a suggestion about "kids" in general, I would agree with you about using the neutral plural pronoun. The thing is, here our friend is replying specifically to OP and offering opinions about what she should do with her son. In that case, I find it annoying and disingenuous to use "they" to talk about the kid, as not only do I find the use of a plural pronoun to refer to a single individual to be a poor linguistic choice, but it is especially so when the subject in question is specifically defined in regard to its gender.

I don't understand why this opinion should be seen as a "gender war," nor why the comment should be received with greater enthusiasm than its mild content implies