2002 Chevy Silverado Transmission problems

In late 2007, my son was in an accident that totaled his frontend and his radiator was replaced. When radiator was replaced, not done correctly and there was a small leak from the top of the radiator fitting area of transmission fluid. Although the truck was returned to body shop 2x in 2008 for continued leakage and worked on in autobody parking lot by professionals, the repair was not done correctly, slow leak continued and as a result in 11/08 the truck would not go faster than 30mph. We were told by another transmission shop "the pan was full of metal shavings when removed and tht 4th gear completely gone". additional damages from this leak at that time that we were toold about were "3-4 quarts low on fluid from leak, burnt 3-4 clutches, 2-4 bands burnt, forward sprag no good, valve body platecheck ball holes too big and worn. The repairs done were plate, bands, clutches, seal, filters, and fluids replaced after almost a years worth of leakage from this top radiator fitting area.
How much damage would this type of leak/fluid shortage do to a torque converter, and or subjection to vast medal shavings and increased temp due to lack of adequate fluids do over this period of time?
My truck just froze up today with no slippage nor warning at a stop light today....just wouldn't move. My first thought is the trannie, and i called the dealer who had repaired the damages from the inefficient leak repairs initially and went to talk with him. The first thing he said to me was "only gonna cover what we replaced last (mentioned parts), but if something else like the "torque converter" has gone out, we wont cover this", as if he already knew this was the problem without looking at truck. I think the torque converter was damaged back in 2008 and they just rigged the trannie to run (only ran 4000 miles after 2008 repairs) and get it out the door. What do you think? Can you help a sister out please?