When you say the leaves are totally dry, would you consider the leaves healthy otherwise? In other words, are they brown and curled or just dry looking but still green?

Are you able to reach the topmost branches? Is so, nick the bark with your fingernail and see if it's green or brown within the margins of the nick. If the branches are alive, the bark will be soft and supple and easily removed with a fingernail. I'm suggesting nicking it, meaning don't make a huge wound, just scrape an eighth of an inch with your fingernail on the new growth a few inches below the terminal of the dry branch and look for life. If the tree farm is correct, then there should be green just under the bark and it will come back to form next year. If it's brown just under the bark, those branches are dead.

I would be surprised if it is not getting enough water on a slow bubbler for two hours each week. Particularly I our heavy clay soils (presuming that is what you have).

Can you attach an image of the tree so that we can see what it looks like?