I think you will find they probably have bought the apartment.As it's illegal for foreigners to own property in Goa,the builders offer them a 5 year lease.Whatever happens after the 5 years is anyone's guess,but they will never actualy own the apartment.
This is the one thing about Goa that is almost impossible to get a definitive answer on.
We have friends who have owned houses in Goa (they had 5 year visas), but have now sold. It is their experiences that have put us off buying.
My understanding is that - there are ways and means to buy a house in Goa, but you will never own the land that it stands on.
This is similar to the feudal system that used to operate in the UK, before we were granted the right to purchase the freehold.
Would you want Mr Shelley to own the land that your house stands on?