ANSWER:

This is a mental condition that needs to be treated by a specialist psychiatrist. 

He’s not sinful if it’s beyond his capacity to control but he must try his best to resist and consult the psychiatrist.

Shaykh i know a brother who has a bad habit of touching his eyebrows all the time and he kind of like pulls on them a little and sometimes an eyebrow comes out and he says “its a habit i don’t mean to do if for beautification or anything like that” there has been 2 times where he has removed a large portion of his eyebrows due to this habit which made him look very odd.