Does the other person have previous work experience? Your daughter is a new graduate no matter how talented she is and how good her marks. If the other person has demonstrated practical work experience in the field (perhaps several years) of course they will be offered a higher salary.

I would also advise you not to publish these details on a public forum. Qatar Airways, like a lot of employers keep an eye on these types of forums and they can easily identify your daughter now and perhaps withdraw the offer.

There is no Equal Opportunity law in Qatar