I have the same experience with you last year; I sponsored my mother-in-law coming here to Doha back then. She came from Oman, and like Saudi, also a GCC country, does not require stamp from the qatar embassy there in Oman to authenticate the VISA. Therefore just verify from the embassy of qatar in Jeddah, KSA, if stamp is not required for the Visa. Another thing, about the return ticket; yes you need to secure it from the ticketing agency where you bought her arrival ticket, since she will be staying here, for one month, I presume, even if she extends or not her stay here.
I have the same experience with you last year; I sponsored my mother-in-law coming here to Doha back then. She came from Oman, and like Saudi, also a GCC country, does not require stamp from the qatar embassy there in Oman to authenticate the VISA. Therefore just verify from the embassy of qatar in Jeddah, KSA, if stamp is not required for the Visa. Another thing, about the return ticket; yes you need to secure it from the ticketing agency where you bought her arrival ticket, since she will be staying here, for one month, I presume, even if she extends or not her stay here.