First of all, when you got married, she knew that she has to live with your parents. She should have told you at that time if she had a problem. Now, you just can’t send your parents to an old age home. It’s your and your wife’s duty to take care of you. Being old makes a person kind of half disabled. They become like a child. It’s difficult for them to remember everything and take care of themselves. Old age is the time when your parents need you the most.
So, try hard to convince your wife that you can’t send your parents to an old age home. If she thinks that she can’t take care of them then appoint a caretaker, who can watch them 24/7.