Humidity control is a very interesting subject to me. In the piano rebuilding business, we discussed this issue all the time. I suspect that ukuleles are not that different from piano soundboards. The wood is dried to the accepted moisture content before assembly. Then, no matter what we do, the wood swells and contracts over and over again, continually for as long as it's still recognizable as wood, splinters, or sawdust. Add water and the wood swells, add dry heat and it will shrink.
The conscientious among us control the humidity the best we can. What we're doing is tempering the changes in the extra-cellular moisture in the wood. But the intra-cellular moisture will continue to leave the cells of the wood continually throughout your instrument's lifetime. This is why we will always find cracks in vintage instruments. Always. Your Favilla, lovingly kept in a controlled environment will, over the course of eighty years of existence still lose the moisture in the cells of the wood. When enough moisture leaves the cells of the wood, it will crack. I'll bet if you took a piece of solid hardwood off the deck of the Titanic (plenty humid), and let it dry, it would crumble between your fingers.
This doesn't mean controlling the environment isn't a good idea. Maintaining an acceptable humidity level in and around your ukulele will, as I said, temper the changes in humidity. These changes in environment accelerate the loss of the woods natural moisture. So, taking good care of your instrument does lengthen its lifetime. And really, eighty years is a good, long life for a thin piece of dead wood.
One thing you might find interesting: Many years ago I was sent a piano from Florida that had "suddenly" developed a crack in the soundboard. The day it arrived in Chicago, it had one visible crack. (there were a couple others under the plate, where you couldn't see them) A week later there were dozens, and the first one was more than an eighth of an inch wide! All the Florida humidity was quickly leaving that hundred old wood. All those decades near the ocean, the instrument was kept humidified, but the wood was shrinking the whole time. I mailed pics (no email or digital photos then) to the customer and frightened him terribly. We had to mechanically dry the soundboard before we could repair it. And, I'm sure there were at least a hundred cracks of various sizes. But, the repairs made it beautiful again and it sounded great. So, the cracks weren't the end of the world.
So too, with your ukulele, the crack isn't really a big deal. I doubt it sounded any different the day after the crack was discovered. It can be repaired. What effects the sound is the gradual, slight shrinking and warping that has been going on all along. But, whether you decide to have it repaired or not, I suggest you keep your uke in Georgia. If you take it to Alaska for vacation, you may not recognize it when you get back.