As a football star and son of the Governor, Tom has fancy sports cars, confidence galore, and all the good things money and power can buy. Unlike, say, Anne Stanton, Tom Stark's wealth and privilege drive him to reckless acts. At first glance, his injury and subsequent death don't seem that connected to either Judge Irwin's death or the deaths of Adam and Willie.
But check this out: Tom's relationship with Sybil Frey leads Willie to pressure Jack to approach Judge Irwin, which leads to Judge Irwin's suicide, which leads to Willie's reneging on his agreement with Gunny Larson, which leads to Tiny Duffy calling Adam Stanton, which leads to Adam shooting Willie, which leads to Sugar-Boy shooting him. Now if you are really smart, connect all that to the story of Cass Mastern.