How bad is his position? Not bad at all. This is a standard business practice: snap up some IP that has huge future value & setup a slush fund to deal with legalities down the road. They knew taking Carmack would get them slapped down the road, but who cares - $500 million is a drop in the bucket for Facebook, which has a market cap of over $350 billion. Their just-reported quarterly profit was over $3.5 billion, so even if they cover all expenses for those involved in the case, they've still made $3 billion overall as a company. Having just paid something like $2 billion for the Rift IP, another $500 mil is just part of the business equation.
And the future of VR is enormous, especially with Facebook integration...imagine the Sims VR with Facebook contacts. Farmville 3D. Instagram 360. The headsets will get Retina-quality eventually, slim down, go wireless, and be easier to use. I'm sure they'll even build the computers into them at some point, with a Kaby Lake card or Intel Compute Stick. Voice commands are getting pretty amazing with stuff like Alexa so you can go sans-keyboard. Why buy a TV or a computer monitor when you can watch a 100' virtual IMAX screen on your 8K Facebook VR goggles?
TL;DR: Media is making it sound like a big deal, guaranteed they planned ahead for this as part of their the cost of business, so it doesn't even matter to them.