Of course you will get some steam/condensation on ceiling in a normal shower but not much splash of actual water up that high. I wouldn't think it is major problem but he should caulk it ASAP. Best to not have any gaps in a bathroom area where moisture might possibly be able to infiltrate inside the walls/framing. He should do it ,but it's not hard to do yourself if you want piece of mind. There should be a matching caulk to your grout color available where the grout was purchased. Sorry you are having to wait so long for the job to be 'finished'.

Big edit for this post, you posted the Kerdi shot while I was typing. So... 1) The flex in the floor that is causing the grout to crack: It's possible that the Kerdi Tray was not properly bedded in thinset, so as the slightly flexible tray flexes, the inflexible grout is cracking. It's also possible that the small size of the penny rounds is resulting in point loading on the foam tray. The foam compresses ever-so-slightly, the tile moves, the grout cracks. The floor...Is your guy using thinset as grout? Grout as thinset? With the penny rounds, it almost looks like he's doing an all-at-once installation. Setting the tile, promoting between-the-tile-squeeze-through, then grouting. All at the same time. A negative with that is that he's grouting and cleaning the grout before the thinset has fully cured. When I grout I'm pretty aggressive with the grout float in order to get grout into every nook and cranny. I don't want to leave any voids. If your guy took it easy when grouting so as to not displace the unbonded sheets of penny rounds, he could have left a few voids beneath the surface. If he wanted to be gentle while cleaning the grout, he might have used too much water during cleanup, that can also weaken the grout. I don't know why the floor is being grouted piecemeal. That's an easy way to get uneven grout color on a floor. As he continues to tile, he'll have to chip out parts of the hardened thinset/grout at the edges fo the already installed sheets to get the subsequent sheets of tile to mesh with the already installed sheets. He'll need to be careful to not ding the Kerdi membrane. It's also a recipe for mismatched spacing at the edges resulting in being able to see the individual sheets of tile versus the floor being one harmonious surface of penny rounds. With him sliding the floor tile under the bottom course of wall tile, I do hope he's not leaving any unfilled voids in the floor-wall corners. 2) Bullnosing. He bullnosed the tile after they were on the wall? Yeah. Probably not going to get a good outcome. Should be an easy remove and replace. The bowed wall? The tiler tiles on what he gets. If he gets a bowed wall courtesy of the framers, he can put the blinders on and tile right over it...or he can address the bowed walls with whoever hired him...the GC? The homeowner? Then the tiler can either tile right over the bowed wall, OR he can have the contractor fix the wall before he tiles, OR he can repair the wall himself and then tile. One added item...I can't tell what exactly is going on int he bottom left corner of the already installed tile. Could simply be that the tile spacing is skewed and he lost the pattern. After this floor is done and everything cured, I'd recommend having the GC pull the drain grate, install a plug, and flood the floor. As the floor tile is covered with water, watch for air bubbles. They'll indicate voids under the tile or in the corners. Once flooded, pull the plug to see how the floor drains. Make sure it drains completely and that water is not held in the corners. With a Kerdi Tray, the slope of the floor and a properly draining floor should be a no-brainer. But based on what I'm seeing and what you described regarding the bullnose, this could be a "no brain" installation. Sorry for that. Remediation after-the-fact is always a tough spot to be in. Good luck.

You have probably already given the contractor more money than he deserves for such lousy work. Insist on a re-do and file a complaint with your state's home improvement commission so legal action can be taken if work isn't redone to your satisfaction. If you don't have a state commission, research what consumer protections are available in your state to help you have the work corrected by the contractor or to receive money back to have it done correctly by another contractor.

They've redone part of it a few times and it still looks awful. That should tell you something. You made a bad hire. The installers are incompetent. It's not going to get better until you get the current 'contractor' off the property for good. Then tear it out and start over.