They have purchased 'points' which they can then use to book stays in DVC resorts at Disney. However, they will still have to buy park tickets, flights and food AND they have to pay annual dues every year which are in excess of $1,000 dollars.
The 'perk' of buying DVC is that you pay one lump sum and you have your points annually for length of your contract (at Riveria it's until 2070). However, they have more than likely bought on finance and I would question whether such a luxury purchase should ever be financed!