Who are Juan Tomas and Apolonia? How is each described?

Juan Tomás, Kino's brother, and his wife, Apolonia are the only two people in the town who really care about the well being of Kino and his family.. When Kino's son is stung by the scorpion, Juan Tomás rush to help them. When Kino finds the pearl, Juan Tomás feels only happiness, not jealousy for his brother. Juan Thomas tries to council Kino on the best thing to do.