My wifes 01 front cat also shattered a few months back which caused the vehicle to severely choke to almost undrivable. I replaced with a rebuilt one from eBay (Cali specs) and it drives like a champ. Lots of power now. The engine light went on again and I need to investigate this before we sell it, since we ended up buying a used X5 to replace the Escape. No other damage that I know of from this. Did he try to change the O2 Sensor that also mounts on that cat. May have been damaged when yours went defective. Also, if the honeycomb broke up in the cat, the the cat (3rd one) before the muffler is probably clogged too. I took mine out and broke out all the honeycomb inside. This would give you a no start since it can't breathe. | 
