PCV/catalytic converter

Some time back, my vehicle began stinking like sulfur/rotten eggs whenever I was accelerating to pass, or accelerating to go up hill. It also started running low on oil quite often. No signs of a leak, no smoking as if it was burning oil, so I figured it was the catalytic converter. I took it to the mechanic and he agreed that it likely was, and that the PCV valve needed to be changed as well. I left the vehicle with him.

When we picked it up, he stated he had changed the PCV valve and flushed the system, rather than replace the CC, "because Toyota doesn't recommend replacing the CC".

2 weeks later, the car was back to stinking in the same situations. We took the car back to him and left it with him. When we went back to get it, he stated the "cylinders are stuck" because of the build up, and that Toyota recommends yet another type of flushing which would run us about $150.00.

I feel like this fella may be incorrect, and that there is the possibility that he either doesn't want to replace the CC, or that none of them in this establishment knows how to do it, or perhaps they don't have the proper equipment. I know that this vehicle has 2 CC, and that it is usually the rear one that has to be replaced, which involves more work.

Should I take the car to someone else, or spend another $150.00 on this "other" type of flush? We're already into him a few hundred dollars for this one problem that hasn't been fixed, and a couple thousand for brake work that doesn't hold for more than 4 months.