There are very few positive characters in this novel. Almost everyone is either gullible, dishonest, or foolish. The exception to this is Miss Watson, the one figure who seems to function as a successful parent.
Huck is coming along in his progress toward literacy and he is being socialized gradually by Miss Watson. She is patient and diligent, both, and these seem to be the qualities needed for good parenting.
Huck's dad is certainly a paragon of inappropriate parenting--he's an abusive drunkard who doesn't care for his own child.
Interestingly, Aunt Polly is a concerned guardian (but not Tom Sawyer's actual parent) who really tries, but Tom still falls in with the poorly raised Huck.
So we have examples of good and bad parents, but the kids end up in the same boat (figuratively and literally) anyway.