fraudulent possession of mothers property.

My maternal aunt lived for some 25 hears in new York USA. On a long term visa she's currently residing in Chandigarh India. She returned in 2006. While she was staying in USA, she provided financial support to her mother who was a widow. She sent money through western money . but later on she opened a joint account with her mother in new York. Thus, her mother had access to the money in the account, therefore making it easy for her. Later in some years my aunt bought a land measuring 5 acres in the state of Punjab. As she was a USA citizen, she named the property on her mothers name. The complete money was hers. Her mother was totally Dependant on her. When they returned in 2006, her mother stayed with her all the time though she had a son here in Chandigarh. Her son was and is unemployed. Her mother names the property on her sons name and the son got the property which my aunt paid for penny by penny. Now the aunt has filed a lawsuit against her brother for the possession of the 5 acres. He is taking defense regarding the authenticity of her properties in USA and in Chandigarh. Please help what can be the strongest point which can be introduced.