Why is Charlie so guilty in Charlie st cloud?

Charlie feels immense guilt in "Charlie St. Cloud" because he believes he failed to save his younger brother, Sam, from a tragic accident. This guilt is compounded by his subsequent ability to see and interact with Sam's spirit, which serves as a constant reminder of his loss and perceived responsibility. Charlie's emotional struggle reflects a deep internal conflict between moving on with his life and honoring the bond he shared with his brother. Ultimately, his journey revolves around learning to forgive himself and find a way to let go.