Income tax treatment

One of my uncle was working in abroad for 20 years and he lot of money, He came to India and build a house in the year 2007 approximate worth 40 Lakhs. In the year 2016 he had his saving and he constructed flat and sold for 30 lakh each for 2 parties. Will these income will be taxable under IT? He constructed flat with the money from abroad which he had deposited in FD.

1. He has never filled his IT returns.
2. Some of the cheque has been deposited to account of his wife and now wife is a agent of insurance company and she is getting commission and TDS has been deducted.