"I'm concerned that I've been driving the car with the bad rack, and given that the steering has been off since it was replaced, and what damage has been done, and to what parts. I'm also not happy that he didn't try putting in sealant before ordering the new rack, (and that I didn't think to try it). What do you think about all this? I'm very concerned that the steering mechanisms on this car with 200,000 miles have suffered badly. Thank you. "

Don't be overly concerned. The defective rack shouldn't adversely affect the steering system in your car.

A few thoughts:
1. Make sure he flushes out all of the old fluid and replaces it with new when replacing the rack. This will remove any metal particles and also the sealant he used.
2. The one component that should be of concern is the aforementioned lower steering shaft u-joint. It has to be loosened every time the rack is removed. It is probably fine, but removing it twice could result in damage.
3. It would be a smart move to put a filter in the inflow hose to the power steering pump. This filter would protect the pump by catching any particles traveling from the rack to the pump. These filters are pretty cheap. If you want to do it yourself you can obtain one from IPUSA.com