Q: When updating OS from Mac OSX 10.6.8 will it support Windows XP Pro and AutoCAD 2011 in Bootcamp mode (VMware Fusion)

What are you updating the OS to? El Capitan and Boot Camp 5.x.x to not support anything but Win 10 and maybe Win 8.

Boot Camp- System requirements for Microsoft Windows operating systems

Boot Camp - Apple Support

Boot Camp 5.1- Frequently asked questions about installing Windows 8

How to install Windows using Boot Camp - Apple Support

Boot Camp Help

Of course running Windows via VM Fusion or Parallels is not the same as using Boot Camp and installing Windows for a dual boot system. If you need to run this particular software and cannot upgrade it for Win 10, then I would suggest you use VM Fusion or Parallels (this is more flexible) and install Windows within the emulator. Then you can install the version you are using now along with your software. For what it's worth there is an AutoCad for the Mac, now, as well as one or two alternatives. These don't require Windows.

If you have existing WXP installation on SL (10.6.8), it will continue to work, but you will no longer be able install a new copy. You should preserve the original WXP installation media for any future repairs.