Remove damaged material and cut the edges of wounds so they are smooth. Apply pruning paint if a large area bark has been ripped from the tree. While current horticultural recommendations for normal pruning advise against the use of pruning paint, it would be appropriate to use it in this situation to protect a large area of cambium from insect damage and water loss. If one side of the tree has sustained extensive damage, prune the healthy side of the tree as well to balance the tree and prevent it from toppling in the wind. Give the tree top notch care including watering and appropriate fertilization for the next few years to help it regain its health.
Lightning is most likely to strike the tallest thing in the area.
Protect valuable specimens by installing a lightning rod in the tree. Client has two live oak trees planted three years ago. One of the trees is now shedding leaves. It could be planted in a low area and overwatered. The period prior to the tree shedding its leaves was very dry so the homeowner could have underwatered if they were watering for short periods of time.