Tell him everything you just said.
At the bare minimum he should replace the receiver/dryer and do an extended pump-down on the system to get the moisture out.
If the holes were wide open and exposed to things like dust, sand, and bugs, then he probably need to do a flush or clean out. Obviously having bits of sand floating around in there will damage the compressor.
You could also have corrosion inside the lines. Not much you can do about that other than replacing the lines.