It's a kind of graphics card that's used in a rig. I can't speak for mining profitability of bitcoin during that timeframe, but if he mined and held litecoins with his 7970's he would have made a killing.
A pair of 7970's would have mined about 150 BTC from Jan. 2012 to Jan. 2013, worth about $2000 USD then but almost $75000 USD now.