your MOM is the answer
Widow Douglas is nice to Huck
Huck hears Injun Joe talking about killing the Widow Douglas. He runs and tells the Welshman who, along with his sons go to save the Widow Douglas.
The widow Douglas tries to reform Huck by being a positive and good role model for him. They also try to help Huck's father by giving him food and clothing.
huck sees Injun Joe and his sidekick near Widow Douglas talking about slitting Widow Douglas's nostrils so he goes to The Welshman's house to tell them about Injun Joe's plan
...I'm pretty sure that he tells the Widow Douglas about it so that the Widow Douglas knows that he's/she's in danger...
Huck decides to live with Widow Douglas because Tom has started a "gang" of robbers and tells Huck that he only would accept those with a good reputation. he compromises with him that if Huck stays with Widow Douglas he will accept him to the gang. reluctantly, Huck agrees.
Tom was going to start a gang, and in order for Huck to be part of the gang, Huck would have to stay with the Widow Douglas
huck saves life because he was folling red joe
both of them try to be his guardian legally by a new judge.
the widow douglas tolerated huck's behavier.