Twisted Treeline Minions invisible

Just played a 3s ranked game. My brother got a bug splat directx error bug splat thing after champ select and reset his game and when he got back into the game the minions and jungle creeps were invisible/untargetable. We held our own in a 2v3 for most of the game and were actually ahead but late game hit and the third member of the team was seriously under-farmed and levelled. We lost that game when we would have 100% won if this error didnt happen. Windows 7, 4gb ram, ati radeon 6770, quad core 3.2ghz amd penom II X4 955. Hes just loaded up a custom game and ran the game as admin (which i dont think would be any sort of fix) and his game seems ok atm. Im thinking though that even if he just rebooted the game normally, his game would probably be ok now. Im thinking if one of us gets booted from the game again and has to reconnect that we are just going to have this same error of invisible minions and would either like a quick fix to get back into the game or a perma fix so it doesnt happen again.