Like other people said, I agree that Terry has definitely helped Sal grow as a person. And I think that having to help take care of Terry and Johnny led him to take responsibility, which is interesting because with all his moving, you might expect that he would try to avoid that.
Also, I liked this quote on page 94: "manana, a lovely word and one that probably means heaven. " It seems like this means that tomorrow holds so many possibilities, but these possibilities could be deceptive. Maybe Sal would be more content staying where he is & not thinking so much about the future.