Potter and Weasley completed the same wandless and silent spells that Draco did.  Potter’s boggart was no longer a dementor though.  Now it was, strangely enough, a scene.  The boggart expanded to a white walled space, a train station perhaps, if Draco squinted hard enough.  Potter, being Potter, didn’t seem to get upset.  Instead he sighed, and cast the spell so that the scene changed to contain a frightening number of haphazard colors.  Weasley’s boggart, predictably, was still a spider.