To accurately determine how Grandpa is best described based on the dialogue in the excerpt, it would be necessary to examine the specific content and tone of the dialogue. If Grandpa displays enthusiasm or eagerness, he might be characterized as excited. If he struggles to understand what's happening, he could be confused. A strong resolve in his words might indicate determination, while a lack of power or control could suggest he feels helpless.
Please provide the excerpt so I can give a more precise analysis.