In the narrative of "I'm Not Stiller" by Max Frisch, the significance of mutual understanding among friends stands out as a critical element for maintaining relationships. It emphasizes that true friendship requires an inherent connection where each party comprehends the other’s feelings and perspectives. This understanding acts as a foundation that enables friends to navigate challenges and grow together while reinforcing their bond.

In contrast, the relationship between brothers is highlighted as an unbreakable bond that persists despite life's trials. Brothers share a unique and deep-rooted connection that remains intact regardless of external circumstances. This suggests that familial ties carry an intrinsic resilience that can withstand various pressures, reinforcing the idea that blood relations often have a lasting impact on one's identity and experiences.