Why do you think Long John was so kind to Jim?

Long John was very kind to Jim who loved to watch in his kitchen to earn his trust and respect. His greed and ambition for money made him cruel and ruthless, in order to get what he wanted he was capable of doing anything. One night Jim heard Long John talking to some of the crew members who were a pirate gang and told them to obey the captain until they got to Treasure Island and let the doctor find the treasure and do all the work and later he and his gang would steal it and kill them all.