Why did the top half of the tree all of the leaves curled up and turned brown while the bottom part is just fine. Can I save this tree or should I just get rid of it?
This appears to be a fungal issue. I believe this to be treatable, though. It is recommended to put down wettable sulfur around the area, and spray with neem oil on the tree as high as you can reach. It is advised to put dolomitic lime around, as well, to control pH so that the fungus cannot thrive as well. Here is a link that will help: https://www.gardeningknowhow.com/edible/fruits/apricots/diseases-of-apricots.htm