Request for doubt

I am from Kerala and working in Central Government Autonomous Body. My father-in-law gave Rs. 5.00 lacs to buy house in 1999. That time we were in Ghaziabad, UP. Due to some family problem, we sold the house in 2007 with an amount of Rs. 13.50 lacs. We constructed house in my land in Kerala using the money of my wife’s. She is housewife. From every month salary I sent money to her account after my expenses. Also when I left my earlier job, I got around Rs. 12.00 lacs towards PF, Gratuity, leave encashment etc. Which also I sent her account. Now her account a cumulative amount of Rs. 20.00 lacs. Also we shifted the deposits from State Bank of Travancore to District Cooperative Bank for more interest. She is not paying any tax for interest of principle amount since she is an unemployed. The amount is accumulated not in one year for the last 8 – 10 years. I want to know whether in case of any income tax verification, she will be questionable for the source of income? I shall be grateful if you could provide a valuable feedback and solutions.