My Husbands Personality Changed So Much That I've Wondered If

My husbands personality changed so much that I've wondered if it can Tia . His speech is often mumbled, he's often very tired, he's become totally unempathic, and has become a hermit. He fell off a grader at work 18 months ago injuring himself and as a result had shoulder surgery. He does experience vertigo. He now cannot lie under a car or truck without becoming very nautous and often vomiting . I have wondered if he fell off the grader due to a Tia. Thanks Krystyna