Oh, undoubtedly, so once he can get sufficient leverage on the bolt, it will either jam the insert against the star so it won't turn with the bolt, or the bolt will simply rip the insert out of the star. Either way, the starnut is toast. Those star nuts are not meant to be tightened very much, just enough to set the headset adjustment. Sometimes people mistakenly overtighten them after the stem bolts are tightened, thinking this is necessary to secure the fork and they get damaged like this. Also, if the star nut is secured in the steerer tube by threading the cap bolt into it and hitting it with a hammer to drive it in, it can be damaged. Best way is to use a proper setting tool.