This reply is late. my apologies beforehand.
He shouldn't boot from an extended partition. Windows can go on a primary.
He can make the system rescue disks. OpenBSD could be next. Linux would be last. If he needs swap then it would be: windows, install linux with swap, add dphys swapfile and edit out the swap from /etc/fstab, use openbsd to utilize the space and eliminate swap, and then edit grub to boot all three.
Again, my apologies for veering off of the subject of OpenBSD.
--- On Sun, 4/18/10, Kim <firstname.lastname@example.org> wrote:
From: Kim <email@example.com>
Subject: Re: OpenBSD Culture? - dual boot info
Date: Sunday, April 18, 2010, 7:24 AM
fwiw - I have Windows XP, Linux, and OpenBSD running on one machine
using two drives, but it should be possible with one.
I would recommend installing Windows first, or if already installed, shrink
the partition using Ranish partition manager or Parted Magic.
Create two new primary partitions and an extended partition.
Install OpenBSD on primary partition 2, GRUB on a small primary partition 3,
and Linux on the extended partition at the end of the disk.
Use the chainloader method of booting with GRUB, where the GRUB partition
is marked active, and it hands off the boot to the individual OS bootloaders
on the other partitions.
See here for more: