Zeepa, I dont see a point why would you make your brother come to Delhi to pick her up. She will be just fine once she reaches Delhi. She will need some help before Delhi and I hope she will find someone from Nepal travelling the same route before Delhi. Tell the flight representative that she need some help (they will write it down on their note). Print the itinerary and give a copy to her and tell her to show it to the flight attendant at New Delhi but I think she will be just fine. My mom used the Bahrain route before by herself and she found a whole gang of Nepalese travellers on plane which helped her out. I know you're little worried but it will work out man.

If Delhi's her final destination : 1. She'll need to go through immigration and "exit" the airport. She'll only be allowed to go through departure gate 3 hrs prior to her scheduled flight. 2. She'll only be allowed one piece of luggage and a carry-on weighing less than 7 kgs (they might not care if it's a tad heavier). If she's going to have 2 luggages, then this is a no-go, IMO. If she doesn't have much to carry, then you could have your brother pick her up at Delhi Airport. But all things considered, having your brother receive her at the airport and "re-enter" is too big of a hassle. Go for Chicago-Middleeast/Istanbul-KTM route (wheelchair). Good luck!