Storm-damaged trees should be evaluated by a professional arborist. A Certified or Consulting Arborist may recommend removal or various improvement measures such as pruning, cabling, lightning protection, root invigoration, fertilization, etc.
The Arbor Day Foundation has a nice page on Can This Tree be Saved? That provides useful information on assessing which trees are candidates for survival and which ones are 'goners'. See Tips for Checking and Caring for Storm Damaged Trees for assessing you tree's situation and cautions to consider.