M104 engine head gasket rebuild

[dubadaddy]

Started with a car that had an oil leak.

Had an indie rebuild an M104 with headgasket, water pump etc...

Problem: Still uses oil. About 2 qts. every 3K miles. Now he says maybe its the rings that is problem.

Question:
1. Should this have been checked when the head was off the car?
2. Is this something the indie should of known prior to doing the head gasket work?
3. Is there something I can do to add to the oil to seal the rings?

I am totally frustrated that he is even suggesting that it could be something as serious as this.