First he should find out what the school is using for video editing software. It's probably Final Cut Pro, but there's a chance they could be based on Adobe Premiere. If it is Final Cut Pro, then the 15" Macbook Pro is a great choice.
Leo suggests getting the 2.6 Ghz Core i7 15" Macbook Pro with the 256GB Solid State Drive, higher-res display, and perhaps a 27" external monitor. The retina display Macbook Pro probably wouldn't be enough of a difference from the regular Macbook Pro, especially if he's already spending more money on an external drive and monitor.
Leo says she should have a local on-site backup in addition to using one of the cloud services. But since she's running out of space on her internal drive, she should get an external drive to have more space to work with. Since she has a newer Macbook Pro without a FireWire port, she won't be able to get a faster FireWire drive, and is stuck with the slower USB 2.0. Apple was counting on manufacturers to make drives for their new Thunderbolt port. No one really is using Thunderbolt yet because the cables are so expensive, and the drives themselves are too.