Jim's gullibility and love to gain his freedom had changed Huck's moral values and had turned him into becoming a responsible person. Until both found a friend in each other despite of their somehow opposite traits. According to Linda Fondrk, in her analysis of how the characters of the Huck and Jim evolved to friendship, indicates the following. A their relationship evolves as Jim proves his worth and wisdom and Huck grows up spiritually and morally. Jim forces him to reckon with his humanity as an African-American and Huck responds by continually redefining and clarifying his values.

After the incident of Huck saving Jim from slave catchers, the two, going on in their adventure, started the bonding of their friendship. From one situation into another, Huck and Jim surpasses...

Both developed friendship to each other, to the point that both can risk their life for the other. Somehow, a parent and child relationship also developed in Huck and Jim. This was shown when the two encountered a dead man who turns out to be Huck's father. Jim warned Huck not to look at the dead man due to the reason that he did not want to hurt Huck's feelings because the dead man was Huck's father.
The friendship of Huck and Jim with each other basically evolved through the dangers that they encountered. Strengthened by such kind of situations, the good friendship of Huck and Jim always came to the point of risking one's life for the other. In general, the relationship of Huck and Jim in the story has evolved in all the adventures that they met where both developed care, loyalty, and trust for each other.

Bibliography

Se-ann Williams. Adventures of Huckleberry Finn. http://blogs.setonhill.edu/Se-AnnWilliams/005483.html

Linda Fondrk. On Huckleberry Finn. http://blogs.setonhill.edu/ErinManko/005404.html