Return of resident outside india

Yes he can submit.

Dear Gaurav, 

It can be filled by the representative assessee if the person is unable to file his return personally. (There is seperate column in ITR page-1)

and yes it can also be filled from any place if the assess is resident of India. 

I suggest you to file it through digital signarute as then there will be no requirement of mailing the acknowlegement to Department. 

Regards

he can submitt the ruturn from anywhere. No issue