Yes, he can. but note u need to cross check with the Qatar Embassy that the profession Sales Exec. can get onarrival visa or not. some of professions are not able to get the on arrival visa. I used 2 come by onarrival but my dubai visa is in the profession of Programmer. All kinds of managers can get the onarrival visa ( I think except Accounts).

Kindly cross check b4 booking the ticket.........