He died at the age of 91 and I think it was just because of old age.
Andrew Wyeth died on January 16, 2009 at the age of 91.
Spouse and children are going to be first in line. Then parents and then siblings.
You can read the North Carolina laws regarding estates in Chapters 28 through 31 at the link provided below.
Yes. He was the youngest out of 5 Children. He died in 2009.