Not if these parents and others encourage it to the point where they won’t allow him to start acting like a boy. There was a lesbian couple who have their 9 year old boy on sex-change hormones.
Pure child abuse
Maybe the parent should make him wear it, then take him to a Rodeo in it. Bring along his britches, and when he decides he should start behaving like a boy, he will realize the foolishness of his thinking.
Basically, it childish thinking looking for attention. You can ignore him and discipline him to get his attention, but it depends upon the volition of the person.
The real challenge is not to ever be happy or satisfied with him arrogantly misbehaving or living in sin.
And that is how that particular case should be considered, as child abuse. Outside the recognition and supervision of a medical doctor, it is also practicing medicine without a license, a state offense, as well as unlawfully providing and administering prescription drugs without a license, a federal offense.
Fortunately, I suspect the number of cases like that are a fraction of all the medical abuses by non-licensed persons out there. And a miniscule fraction of child abuse cases.