They did it by paying attention to mom and dad.
Sorry, there must be more to it than that. Did you help them? Nothing wrong with that. My parents wouldn’t lend me $10,000 for a week when we put down our deposit on our first house although we had jobs. We had to borrow it from good friends - much to my embarrassment - who got it back in 7 days. They were Depression people and very tight with a buck.