That looks worse then my Father-in-Law's iPod Air 2 that he dropped on the power button corner. He's been looking at the sale prices waiting for something in the $250 range for WiFi only and 16-32 GB of flash. As you observed, while it is possible to get the screen, glass, digitizer, etc. separated, it's a mess to do so. A broken screen/surface glass is the only reason I would, since those components are the most likely to be damaged in the removal process. I have not added the iOpenner to my iFixit toolkit which also means I'm unlikely to try repairing my FiL's iPad. Since his case is mangled around the power button as well (it's wedged into the case) replacement of the entire iPad is his best option.
We used clear packing tape to keep the missing shards of glass from slicing up his fingers. The iPad's camera is clearly exposed so it's a good thing he doesn't want to take any pictures with his tablet. But it still works well enough for most of the things that he wants to do; as a result there isn't much impetus to replace it.
This sounds like a good project for Grandpa and grandson! Have you been keeping him involved with the repair? When I was his age, I was taking apart alarm clocks and putting them back together.