Property registered under duress

My 97 year old grandmother whom is currently being taking care of by her daughter has recently transfered her name onto the title of my grandmothers property. My grandmother son (who is my father) is not on title. There is reason to beleive that this decision was done under duress from her daughter (my aunt). Can this be overturned? Is this a common case?
How successful are this type of cases. Can it be overturned by my grandmother soley or does my aunt have to agree to also allowing my father to be on title aswell?

Yes--you can file in court and have the circumstances reviewed and the court can void the transaction. It is often done.