The Scottish Rugby Union announced his death on Sunday. In 2022, Hastings said he had been diagnosed with non-Hodgkin lymphoma and the SRU referenced a family statement that said he "deteriorated extremely quickly" due to complications with his treatment.
"He passed away peacefully and pain free," the family statement read.
The most-capped centre in the history of Scotland's men's team after making 65 appearances from 1986-97, Hastings was a member of the Grand Slam-winning team in the 1990 Five Nations and scored 10 tries for his country.
He and Gavin, who was three years his elder, made their first Scotland starts together in the 1986 Five Nations in a win against France. The teams shared that title.
Both were picked for the 1989 Lions tour of Australia. The Wallabies won the first Test comfortably and, thanks to a midweek comeback win over ACT, Scott was brought into the centres along with Jeremy Guscott among five changes for the second Test. Scott and Gavin were the first Lions Test brothers since 1910.
In what became known as the Battle of Ballymore, the Lions stood up to Australia but trailed 12-9 with five minutes to go.
"We got a break out ... and I realised there was a huge gap on the outside," Scott told the Lions website. "Being a left-handed player I thought I could fire this pass out but it was more like a big loop that bounced and my brother Gavin went over and scored.
"As he ran back he said, 'That was fantastic, what's the score?' and he hadn't realised he'd put the Lions into the lead."
The Lions prevailed to set up a series decider in Sydney, where they won again 19-18 and became the first Lions to win a series from 1-0 down.
"I pulled off a tackle in midfield against David Campese that I really enjoyed but when that final whistle went, (it was) that sheer joy of winning a Test series," Scott said.
He also went to New Zealand in 1993 but his Lions tour was cut short before the Tests when he broke his cheekbone on Josh Kronfeld's knee.
Former Scotland and Lions coach Ian McGeechan told the Scottish Rugby website: "I remember Scott on the Lions tours taking an absolute lead. He was so single-minded and determined about winning.
"He was very much your right hand man, given what he did on the field.
"Whatever jersey Scott wore, he just made it better."
He played his last Test for Scotland in 1997 with current national coach Gregor Townsend.
"Like many other schoolboys throughout Scotland at the time, I wanted to emulate Scott's approach to the game and how he took the game to the opposition," Townsend told Scottish Rugby.
"Scott always brought positivity and energy into everything he did from his playing career then into the past couple of decades as a widely traveled and respected commentator."
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