Ask Mr. Smarty Plants

Auracaria heterophyll, Norfolk Pine, is endemic (grows natively nowhere else) to Norfolk Island, a small island in the Pacific Ocean between Australia, New Zealand and New Caledonia. This article from the Gymnosperm Database has more information.

From Floridata here is more information on the cultivation of your tree. You should especially read the portion on Hardiness:

"Hardiness: USDA Zones 10 - 11. Norfolk Island pine is very tender and will begin to sustain damage at temperatures below 40ºF (4.4ºC) beginning with discoloration of foliage. In Florida the Norfolk Island pine is grown in warmer and protected micro-climates throughout Zone 9 - especially near the water. If the tree is killed by frost new stems will be produced from the roots."

Since Nueces County is in USDA Hardiness Zone 10b, the tree should ordinarily be okay there but, as you say, temperatures have been very strange this past year. The Lady Bird Johnson Wildflower Center is committed to the growth, propagation and protection of trees native not only to North America but the those areas in which the plants grow natively. Since your tree is not native, we have no information in our Native Plant Database to help us out, nor do we have personal experience with it. The best we can figure out from the various articles we referred you to is that you should trim away all dead or browned branches as the needles will not grow back. It does appear to need a good deal of water, so in this dreadful heat and drought in Texas, you do need to be giving it deep watering. As for what to do next Winter, that probably is going to be the best you can. If the tree is already too big to cover if an extreme cold is forecast, you'll just have to hope for the best. If it gets very large you should take note of the fact that large trees in Florida and Southern California have broken and fallen in high winds or hurricanes. It apparently is a rather brittle wood.