Does he not have a ring compressor? All of the rings need to be checked for end gap in their corresponding bores. This should have already been done before trying to install them. If he hasn't done this then I would take my toys and go home.

I would not replace the cam towers. You would be asking for trouble. Make some simple flat block off plates with a gasket under them. Not too hard to do really

31 minutes ago, Jon Dickson said:

He has also had quite a bit of trouble collapsing the oil rings on the pistons. Any tricks that I can send his way. He said that the red and green need to be butted up against each other and with them butted he has not been able to collapse the ring.

 

The red and green are meant to be visible.  The parts that need collapsing are the two scraper rings, top and bottom.  Shouldn't really be affected by the red and green middle spacer.  Maybe they're the wrong rings.  Easily test-fitted in the cylinder before installing on the piston.  Odd problem.

https://www.mahle-aftermarket.com/media/media-global-&-europe/products-and-services/engine_components/piston_ring_sets/en_kolbenringe_poster_a1_final.pdf