Foreign income

Dear Sir / Madam, 

My Friend has working in India till Sep 17, after he was working for Japan Company & done Employment Contract from 10th Oct 17 to 31st March 18. 

Indian Salary Is 143733 & Japan Income is 807943 (1279200 * 0.63) after deducting Income Tax, House Rent & Local Tax.

My Question is how to file his ITR?????

is his income taxable??