What are instances in Cold Sassy Tree that proved to be "coming of age"?

The novel follows Will Tweedy, age fourteen, through the process of losing his grandmother, trying to understand his grandfather’s quick remarriage, and ultimately losing his grandfather as well. Will had deeply loved his grandmother, Mattie Lou, and understood that Grandpa Rucker Blakesee was wholly devoted to her. All the other family members are outraged when Grandpa Blakesee decides to marry a much younger woman, Love Simpson, and they elope three weeks after Mattie Lou’s funeral. Although Will does not speak much about the new arrangement, he emotionally support his grandfather.
After the couple marry, Will is privy to many of their conversations, as they are sometimes unaware of his presence. Thus he learns the secrets that prompted Love to marry Blakesee. In this way, he learns about sex, including incest and rape. Love’s own father had raped her when she was only 12 years old. As Blakesee and Love move from having a platonic marriage of convenience to becoming sexual partners, Will’s understanding of the couple’s relationship matures. He also develops a crush on Lightfoot, a newcomer to town, and kisses her. Later she tells him she is marrying another man. At the novel’s end, Grandpa Blakesee also dies and ensures Will can go to college with his inheritance. Thus, although Will does not come of age in terms of a sexual initiation, he moves steadily toward adulthood.