Those could be Leland Cypress or Giant Green Arborvitae. They are very similar. Regardless, your tress should not be turning brown. They are evergreen. If he bought them from a reputable dealer, even a big-box store, I would imagine he could return them for a refund or replacement. I have a feeling that the tree(s) were mishandled (probably not watered for a long period of time) before he ever purchased them. How did he transport those trees home?
Here are my stand of Green Giant Arborvitae that were 6' tall when planted 2 1/2 years ago. The trees are now approximately 15' tall. The picture was taken just after a snow event last week.
night
early morning
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early morning
