The low end 15" MBP will suffice. You need screen estate to edit, so a 13" will be out of the question.
Tell him to go to an Apple store and look at the 15" MBP, HiRes display and non high res. Remember non glossy version costs more too.
4GB is Ok, but he can buy 8GB+ himself and install it. Save a bunch of money.
Also get a 7200RPM drive if you're going to edit internally. Should be enough for HDV or H264.