Final answer:
Tom Buchanan's experiences have changed him, leading to changes in his personality and behavior.
Step-by-step explanation:
Tom Buchanan's experiences have had an impact on his character. Before the accident, he was described as hardworking and amiable. However, after the accident, he became irritable, temperamental, and lazy.
While some of these changes may be attributed to alcohol used as a pain medication, it is clear that aspects of his personality did change. Despite the dramatic shift in his life, he was still able to function as a stagecoach driver, showing the brain's ability to recover from major trauma.