Fry79, you must be very excited for her to come and now very worried as well, but relax. Everything will go just fine.

Just tell your Thai lady friend to put on a nice dress that would make her look very respectable and professional, like a business traveller. So no shorts and t-shirt, and no spaghetti straps or some other sexy outfits that would make her the center of attention at the airport.

With the long lines at immigration counters in Doha, the immigration officer will not bother to check closely whether she is really a tourist or not. As long as she has the proper passport and visa and confirmed hotel accommodatio, those should be enough.