Yep, this anon is correct. "The Family" funded the Grateful Dead through their sale of LSD in the late 60s. Many books delve into this topic, first hand witnesses recounting all the musical artists who took LSD with the Grateful Dead.
Jefferson Airplane, Jimmy Hendrix, The Beatles, pretty much everyone who lived or traveled around L.A. and San Fran during the 60s and 70s.
Great insight here in this book, its a fantastic and intriguing read: https://www.amazon.com/Bear-Times-Augustus-Owsley-Stanley/dp/1250081211
Wiki page on Owsley Stanley:
https://en.wikipedia.org/wiki/Owsley_Stanley