First, I'm assuming you mean that you have a System Recovery system from a manufacturer because Microsoft does not include Office on a Windows CD. In that case, it's almost impossible to strip Office from the recovery CD and burn it to another disk.

Second, such OEM software is locked to the OEM version of Windows, which is, in turn, locked to the OEM hardware. This prevents someone from installing the software on multiple computers.

Finally, even if you could somehow make it work, doing such is illegal. Unless otherwise specified, a copy of Microsoft Office can only be installed on any one desktop and any one laptop, both of which are for the primary use by the person posessing the license to Office. In your case, the restrictions are even tighter, with the software only allowed to be used on the one specific computer.

Personally, I'd suggest that your brother-in-law either obtain a copy of Microsoft Office the legal way, or download the free, open-source alternative Open Office. It's compatible with MS Office, and boasts most of the same features/abilities, but at no cost to the user.

Hope this helps,
John