My brother earns 480,000 yuan a year, and his sister-in-law suggested that every month she help her younger brother-in-law pay 3,800 yuan toward his car loan.

Ha—my brother didn’t agree. He never expected his mother-in-law to come up with a bad idea, threatening divorce to coerce his sister-in-law.
But my brother’s cousin didn’t buy into that at all; he promptly went through the divorce procedures.
After the divorce, the sister-in-law still fantasized that her husband’s cousin would be unable to live without her—that once his temper cooled down, he would come back to find her.
Now divorced and with nowhere to go, the sister-in-law can only return to her parents’ home.