Belated returns from 2010-11

Good Morning

One of my client has not uploaded his ITR since AY 2010-11 and later he got a notice from Income tax department for his returns, however no section has been specified in the notice. Can be file the returns now, he has just the salary income for two years. Later his residential status is of an NRI as he has been shifted to out of india for work. 

Please advice how he can file the return for the two years and what about the rest of returns after bening an NRI, do we need to file a return for the same.

Thanks 

Anirudh LG