Unregistered wastepaper scrap business on daily basis

My friend do waste paper business on daily basis.He purchase some waste paper like waste carton boxes, waste newspaper, waste textbooks etc from kirana stores and sell it wholesellers in the market. He does all transaction in cash. He has no registered business and no vat certificate nothing. He earns good income in the range of 2.5 to 3 lacs per year. How he has to file his returns under which section. please guide.