River Phoenix ... remembered by his sister Rain Phoenix on what would have been his 54th birthday. Rain, 51, took to Instagram to share a series of nostalgic photos of her late brother, including ...

River's sister Rain Phoenix also honored her late brother with a throwback photo and memorable quotes of his Frank Trapper/Corbis via Getty Images River Phoenix and mom Arlyn "Heart" Phoenix River ...

On Wednesday, Rain Phoenix shared two throwback photos of River to Instagram to mark his birthday, almost 30 years after the Stand by Me star died from a drug overdose on Oct. 31, 1993.