Huck helps Jim all the way. First of all, he helps him by not turning him in. Also, he helps him by staying with him throughout his journey. I don't want to go into the details, but you should read the book and I am sure that you will find the answer to the question in there.
Good Luck Mate!!!
Huck doesn't turn Jim in because Jim in Huck's first TRUE friend. Jim is also the only "family" Huck has ever had that cares so much about him and will protect him.
a wigwam
There is never a reference to how he actually died in the novel. Jim and Huck just find a body in the house on the river. (Important to note that Jim turns Huck away from the body, as a way to protect him!)
Jim always cared for Huck like a son and tried to protect him throughout their adventures on the Mississippi River. He showed loyalty, compassion, and kindness towards Huck, becoming a father figure to him.
a wigwam
Jim kept the dead man's identity a secret from Huck to protect him from the harsh reality that the dead man was Huck's father. He wanted to shield Huck from the emotional burden and potential trauma of finding out the truth about his family.
He wanted to protect him from the knowledge. Also, internally, he knew that if Huck didn't have a reason to be hiding out on the island, and later to head towards "free territory" than he himself would be out of luck.
He told Huck that Jim had been sold as a runaway slave!!!
Jim is initially startled when he sees Huck on the island, as he believes that he has seen a ghost. However, he quickly realizes that Huck is alive and is relieved to be reunited with him. Jim is happy to see Huck safe and well.
Jim is initially angry at Huck for playing a trick on him, but he eventually forgives him after seeing how upset Huck is. Jim understands that Huck didn't mean any harm and values their friendship more than holding a grudge.
No clue
Huck liberated Jim and helped Jim realize who he was!