Final answer:
The son can attempt to set aside the contract of the house sale by proving that the caretaker exercised undue influence or engaged in elder abuse by taking advantage of the senior citizen's frailty and dependency.
Step-by-step explanation:
The son may contest the sale of the house under the legal theories of undue influence or elder abuse. Undue influence occurs when a person in a position of trust, such as the caretaker, exerts excessive pressure on a vulnerable individual, leading them to make decisions that are not in their best interest, such as selling a home for significantly less than its market value. Elder abuse can be financial, physical, or emotional, and encompasses any situation where the caretaker intentionally harms or exploits the older person.
In this scenario, the son can argue that the caretaker took advantage of the senior citizen's frail state and her dependence on the caretaker's support to secure the home sale for much less than its worth. This could be construed as a violation of the care and trust placed in the caretaker and is particularly concerning in light of the existing warning by the senior citizen's son.
If elder abuse or undue influence is proven, the court could declare the contract void and set it aside, restoring the property to the senior citizen, or possibly enforcing a fair market sale of the property.