Tragically, some people are absolutely heartless and think nothing of exploiting those who are helpless or weak. Perhaps your letter will encourage people to be more alert to these dangers, especially if they have friends or family members who may be vulnerable. The Bible says, "Blessed are those who have regard for the weak" (Psalm 41:1).
Why do some people act so cruelly? The reason is because they're concerned only for themselves. They never would want anyone to treat them this way, but that doesn't bother them, for they think only of themselves. They think this way because they've left God out of their lives, and have allowed their sinful human nature to control them. The Bible says, "In his arrogance the wicked man hunts down the weak, who are caught in the schemes he devises" (Psalm 10:2).
Do what you can to help your mother-in-law, including getting legal advice concerning this contract and whether or not it can be cancelled. Remember: Your concern shouldn't be just for her, but also for others who might be taken in by this scheme. In addition, it may be time for your husband to take over your mother-in-law's finances; her lawyer can advise you about this.
In addition, ask God to help you be a blessing to your mother-in-law during these latter years of her life. She took care of your husband when he was young and helpless; now ask God to help you care for her. Remember the Bible's command: "Honor your father and your mother" (Exodus 20:12).