Who is James Tyrone Jr. from A Moon for the Misbegotten and what is their importance?

Jim Tyrone is in his early 40s. He is a hard drinker and his face and body show it. He had been sober for two years but when his mother died a year ago, he started again and hasn't stopped since. He is in town settling his mother's estate. He plans on selling the farm to Hogan, for a low price.