For travellers in Economy the minimum is eight hours, while for First/ Business travellers it is six hours. Some fare classes are not eligible and the traveller needs to be arriving and departing on an EK
flight and on a single ticket.
Failing that, depending on what credit card she has, she may be eligible to use the Mahaba Lounge. Some MasterCard holders may use this service. I haven't used this particular lounge so I can't say what it's like. If lounge access is not an option, there are a couple of rooms set aside for prayer and contemplation. There are also a couple of pleasant, though not very large, water-garden features.
is huge, but fortunately T1 and T3
are linked so that she can walk from one to the other. Both have the usual array of shops that you see in most major hubs, including designer clothing and handbags, electronics, books and jewellery. But even the most dedicated shopper would find it difficult to fill in seven hours. There are also outlets of Häagen Dasz (spelling?) Starbucks, McDonald's and others.
Otherwise my tip would be find a seat and make sure you have a good book if you find sleeping impossible.