Is Trexler's reaction to his discovery of what he wants in life realistic? Why or why not?

I inferred you are referring to the story "The second tree from the corner".

Answer:

No

Explanation:

Note his response to the psychiatrist when he was asked about what he wanted, Trexler said: "I want a wing on the small house I own in Westport. I want more money and leisure to do the things I want to do".

What he wants is not realistic because having a "wing on the small house" isn't structurally possible. Also, his mental state would not allow him to have "more money and leisure to do the things" he "wants to do".