What is Walton’s impression of Frankenstein?

Victor astonishes Walton by asking him where he's heading before boarding. Walton cannot believe that a man in so desperate a circumstance would ask such a question.

You may conceive my astonishment on hearing such a question addressed to me from a man on the brink of destruction and to whom I should have supposed that my vessel would have been a resource which he would not have exchanged for the most precious wealth the earth can afford.

Good God! Margaret, if you had seen the man who thus capitulated for his safety, your surprise would have been boundless. His limbs were nearly frozen, and his body dreadfully emaciated by fatigue and suffering. I never saw a man in so wretched a condition.