Your views on Renting a 2BHK flat with heavy deposit.

Hello Thanekars, Need your honest opinion on this. My in-laws (both in their mid 60s) are selling their appartment in Lokmanya Nagar, Thane around 30 lacs (as you know most of the buildings are illegal) and planning to rent a 2Bhk in Vihang Project, Kasarvadavli on heavy deposit. The person is asking around 12 lacs for the same which I am finding is too much. For the area and appartment size, this seems incorrect too. Plus, is renting on heavy deposit is good idea? I have heard some negative views as well. Or Paying rent on a monthly basis good option using SWP (Systematic Withdrawal Plan) This is the only money they would have for themselves. There are no FDs, MFs, Cash or even Insurance. We have added them in our Corporate Health Plan for Insurance. Kindly share your view points. Thank you in advance.