Mr. Lamb helped Derry because he wanted him to change his view of life. This answer can be inferred from the context and events described in the story.

Explanation:
1. Mr. Lamb's empathy and understanding:
- Mr. Lamb is portrayed as a kind and compassionate person throughout the story.
- He understands Derry's struggles and tries to connect with him on an emotional level.
- This empathy suggests that Mr. Lamb genuinely cares about Derry's well-being.

2. Derry's negative outlook on life:
- Derry is initially depicted as a bitter and resentful young boy.
- He harbors anger and hatred towards the world, blaming it for his physical impairment.
- Derry's negative mindset prevents him from seeing the good things in life and hampers his personal growth.

3. Mr. Lamb's efforts to change Derry's perspective:
- Mr. Lamb takes Derry under his wing and becomes his mentor.
- He introduces Derry to new experiences, such as swimming and sailing, to broaden his horizons.
- Through these activities, Mr. Lamb aims to show Derry that there is more to life than his disability.
- He wants Derry to see the beauty and joy that still exist in the world.

4. Mr. Lamb's patience and support:
- Despite Derry's initial resistance and skepticism, Mr. Lamb remains patient and supportive.
- He continuously encourages Derry to challenge his negative beliefs and embrace a more positive outlook.
- Mr. Lamb's unwavering dedication to Derry's well-being demonstrates his genuine desire for Derry to change his perspective on life.

In conclusion, Mr. Lamb helps Derry because he genuinely wants him to change his view of life. He understands that Derry's negative mindset and resentment are hindering his personal growth and happiness. Through his empathy, support, and introduction to new experiences, Mr. Lamb aims to show Derry that there is still beauty and joy in the world, despite his physical impairment.