Many people suspected that his hang around friends were lacing his food with even more LSD than he was already taking, he got to the point when they were playing in the London Underground where he would just stand on stage and play one note over and over and over, and then spend 20 minutes detuning his guitar. It had become an unworkable situation, David would step in and they would start playing over him, it got to the point where they wouldn't tell him when they had a gig and David would coome in and play lead. Syd would find out and show up at the gigs and sit in front of the stage and just glare at Roger Waters, but the band really had no choice, Syd was totally gone by this time. At about this time Tim Renwick started sitting in with the band and actually performed a lot of uncredited work on Atom Heart Mother and pretty much became their studio musician and toured with them everywhere, it is him playing acoustic guitar on Wish You Were Here. When they were recording that particular song for the album, who walks into the studio but a disheveled, dirty, and totally incoherent Syd Barrett, strange indeed. Shine On was a direct tribute to Syd and after Syd's "friends" had drained his finances, the band set up a trust and made sure no one could touch his royalties from the 2 Floyd albums, the 2 solo's and all the songs he wrote that they ultimately recorded. HE actually was living a fairly comfortable quiet Englishmens country life when he died.
I too read what David Bowie said about Syd, I had known for years that he credited him with being the absolute biggest influence on his music, I guess that's why Bowie is such a huge Flaming Lips fan.