I think it could. Yusuke's spirit gun was only capable of destroying a hill (and not the whole thing at that) and Aang has strong winds and earth beanding to block those attacks, not to mention he could just deflect it with an offensive attack of his own. Anyways, if Yuske hits him it's over, but I don't think it'll be that easy with Aang being covered by a wind barrier the whole time.