Let's not act like he was just some guy who had mental health issues and they threw him to the curb. A big part of the reason Barrett had to be replaced was because he was constantly tripping on LSD and wasn't able to perform during concerts.
No but that doesn't change the fact they stole from him and relatives/friends have said he died broke....
I do not know what source you got your info from 'Koast but it is DEAD wrong, and is a great disservice to the Floyd, they knew what Syd had meant to the band, they lauded and lamented him in song for years afterward, and they made sure he was taken care of until his death from pancreatic cancer (not diabetes, as has been reported), so allow me this opportunity to set the record straight.
Syd Barrett did not die broke, he died as a recluse living a quiet life in his mothers house ( she had died years earlier) in Cambridge, his sister Rosemary looked after him, and the band provided for him and his care untill his death. In fact, even though he had no royalty rights because of the way things were done in the '60's, David Gilmour and Rick Wright made sure he was included in the bands royalty revenue, including 2 albums he never had anyting to do with, Wish You Were Here and The Wall. Wish You Were Here having been directly inspired by Barrett and The Wall based loosely on his spiral into insanity (if indeed, he really was insane). Syd never wanted for anything financially and was happiest in his garden, and chose to have little to do with music or Pink Floyd after his 2 solo albums were released.
Pink Floyd DID NOT steal any of his songs and in fact several songs he wrote and they recorded for Saucerful of Secrets never made the album and have never been released. Roger Waters and David Gilmour were very talented writers themselves and would not have needed to steal music from anyone, especially someone they both held in very high esteem.
Syd Barrett's problem was he was a massive drug user, LSD being the drug of choice, and he surrounded himself with friends other than his band that fed his obsession with it, some even accuse his "friends" of secretly lacing his food and tea with acid to keep him stoned. Waters and Wright realized the band could not continue this way and so they subtley pushed him out, bringing in their session and stage guitarist and only really talented musician, David Gilmour, to replace him, Barrett used to sit in the front row and just glare at his old friend whenever they were performing, and yet Gilmour fought more to take care of him than even Waters did, but they all knew that for the band to survive, its creator had to go.