Final answer:
Andy's mind is changed by his own personal growth and new understanding of relationships through overcoming homesickness and making friends at camp, leading to his decision to support Nellie's adoption.
Step-by-step explanation:
Andy's decision to sign Nellie's adoption recommendation form is rooted in his experiences and personal growth. Initially, Andy's bad behavior and reluctance stem from homesickness and discomfort at summer camp. However, as Andy overcomes his homesickness by making friends and pushing himself to study music, he displays a significant change in character. His newfound courage and determination pave the way for his willingness to support Nellie's adoption. It is Andy's personal journey of overcoming challenges, including a fight with another boy that leads to a deeper understanding and empathy towards others, ultimately influencing his decision.
The final act of signing the form is a testament to Andy's growth and his recognition of the importance of supportive relationships, exhibited both in his interaction with the other students and counselors and in his understanding of family dynamics, as seen in various literary examples throughout the snippets provided.