Have you heard of the term "undue influence" in estate planning? It essentially means that a person who is crafting an estate plan does so in a way that benefits another person because of that person's influence on them.
For instance, say a man has $500,000 to leave to his two children. He plans to leave them $250,000 each. Then he moves into an assisted living center. When he passes away, the children find out that he left $400,000 to his main caregiver at the center, while they now get just $50,000 each. They may argue that the caregiver exercised undue influence to convince the elderly man to change his will.
One of the keys to undue influence is that someone needs to be a vulnerable party and the other needs to be in a position of trust or power. The caregiver-resident relationship is a perfect example. The elderly man may have felt that he had no other option but to change his will or he would not get the care he needed. Even if it was not something so direct, the caregiver may have subtly manipulated him for weeks, months or even years, trying to turn him against his own children to exploit him for his wealth.
The law recognizes that many people find themselves in these vulnerable positions, which is why undue influence is illegal. You can contest a loved one's will or other documents in their estate plan if you believe that they don't reflect that person's true wishes. An experienced estate planning attorney can help you if you believe you have grounds to do this.