Income tax

when he left for employment ??if he left before October then he will be treated as resident as per sec6(1) of income tax act and his global income will be taxable,then u have to file ITR1 .in other case he will be non resident and income earned outside India is not taxable and file ITR2 for claiming any tds or other refunds from ITD

Yes. If he satisfies condtitions of Sec 6(1) then he has to file the ITR 1 for AY 2019-20.

Otherwise he need not file his ITR.

check his passport Immigration stamp departure date from India .. calculate no of days of stay in India  from April 1st ...(below or above 182 days) below182 days stay in India qualifies as NRI ..then file only income earned  in India -if income above 2.5 lakhs or to get any refunds ... If stay in India is more than 182 days - file both indian & foreign income.