Almost any phone can be used here in qatar, as long as it is not "blocked" but then again there are som many places here that can "un-lock" your phone.
Ask your frined to go to any Q-tel shop [qatars only telephone company] and buy a prepaid sim.
you wil pay 50Qr, and that includes 50Qr call credit.
Only need to bring passport if she does not get qatari id.