Navigation: Diary | News | Rumours | Rubbish Bin | F.A.Q. | Fan Sites | Biography | Extra Stuff | Wizard of the Month Archive | Happy Birthday | Links
As of the end of Half-Blood Prince, he has no idea how to produce one, so nobody knows. You must remember that the ability to produce a Patronus demonstrates an advanced level of magic not routinely taught to young Hogwarts students (hence the surprise of the prospective members of Dumbledore’s Army when they find out that Harry can make a Patronus).