Answer:
I think that Taylor wants young people to understand, that no matter what the skin color, or the race, treat people equally, because one day, they might be your only way of survival.
In the story of <em>The Cay</em>, Phillip learns to realize that Timothy was his only way of survival, even though in the beginning, he thought that an old black man wouldn't be any use for him. Turns out, he was wrong, he began to realize that Timothy wasn't only an old black man, he was a friend.
I personally think that Timothy would be one of the greatest friends that Phillip might have, because it is very rare for a friend, anyone in fact, to barely risk their life to help save someone. Especially when you must experience being blind and having to rely on someone for survival.
(Sorry if this is late)