Nothing, she is using all the bandwidth to do her massive upload. She can try using 7 zip to compress the files before she sends and see if that frees up some bandwidth. ATT may be throttling you down as well, thinking you are a bandwidth hog during those times.
AT&T "assured" me that they would never throttle back a customer when they use a lot of the bandwidth. They also told me that with my 6 meg speed package they spread the bandwidth over all connected devices. So basically I just have to deal with it...