Globe/Globosa Blue Spruce is dying from top down - HELP!

Can anyone please give me insight into why my Globe Blue Spruce seems to be dying from the top down, and how I might protect it? Please see photo! It gets a lot of sunlight, and seemed to start dying after the hot, dry spell this summer here in Oklahoma. I tried to water it more thinking it was too dry, and it only kept dying downward. What you see has happened in about 3 months.