The black drain stuff looks like abs, but the white water supply stuff should be CPVC, not PVC. CPVC, done properly should be fine. Copper wouldn't get brittle with age, though.
It looks like greenboard going up. Realize that the national codes no longer recognize greenboard's use for much of anything in a wet/damp area. It really doesn't hold up an better than regular drywall in the real world. If it is a wet area, then a cbu is called for, otherwise, a good primer and top coat of paint is more than sufficient. Greenboard isn't as strong as drywall, either, and it's use on the ceiling is sometimes problematic on a longterm use - it tends to bow if the supports aren't closer than the normal 16" oc.