Hi, John, glad to hear you're enjoying the game up to now.

Let's see what we can do to get you unstuck.
I myself went back and played every topic of Wolfgang's call with no freeze. So I'm not sure how game-based this is.
We've had a Nook HD playthrough done by a playtester before, though not sure if it was the same model as yours.
So given those points, there are 2 options I can think of offhand:
1. You may need to free up some space in your storage.
Gabriel Knight requires at least 2GB of space. So I may suggest confirming you have at least 1GB free after install.
2. Debugging and tech support.
Your Nook model I see is from 2012. In the tablet world, it could mean your tablet is a bit old. This wouldn't be something we can control too well.
If you're interested, we can give you a debugging kit to help us get info from your device as you play, but that would require some technical work for you.
Or you can see if anybody else has similar issues with games getting stuck on your tablet model. I'm not sure how B&N supports the Nook but I did see they're not selling your model anymore, so I'm not sure how to recommend checking for official tablet tech support on current games.
In the meantime, I'm asking our developers to see if they have any other ideas to help.
And I'm attaching a save right after the Wolfgang call for you to load so you can continue with your sons without having to wait.
Just tell them that Gabriel got a lead to go to the graveyard.

Please rename the save file as necessary (the number 02 can be edited to whatever other 2-digit number you want, make sure it's not a number currently used) and put into your Android/data/com.postudios.gk1/files folder.
Let us know how it goes and I'll write back if we have anything new to report from here.
Thanks, John.