I have used Vegas a bunch'o times
If your firend is using Sony Vegas, he should be able to export to MPEG 2. MPEG 2 is the format used on DVDs, so DVD Studio should be able to handle them.
Also make sure everythings in NTSC (Region 1) not PAL or some other format, or you'll only be able to play the DVD in Europe. You just want to make sure that all the stuff lines up & is compatable. Probably will be by default, but it doesnt hurt to check.