Chances of hacking facebook are low, even if you could it would take you months of research to get anywhere at all. Most people recycle passwords so if you can build a list of easier/alternative targets you can possibly dump the pass out that way. His/her home pc is probably the weakest link in the chain, so if you can redirect him/her to a spoofed site with some flash and/or MPEG with faulty header data etc, there is a possibility something will drop you into running code on stack or whatever. However most people keep their system fairly up to date and you'll need to be dedicated and keep looking for an entry point.
Good luck, and remember to synchronize with the universe and life prana.