Residential status

One of my client (Indian Citizen) went abroad for job in January 2013 and returned in the 3rd week of October 2013. What will be residential status as per Income tax Act for F.Y. 2013-14 i.e. A.Y. 2014-15. And If he become NRI, whether he requires to file return of income for the  F.Y. 2013-14.

Hope for your early expert advise.

Thanks.