His dad may have been the inspiration, but I think he was mostly talking about himself and Syd Barrett. Wikipedia has a pretty good write up about the song and album.
Specifically because of bands like Floyd, Zep and Black Sabbath, I learned early not to dwell on the lyrics. Lyricly, Waters was all over the place back then. It is cool to see Waters perform live now though. Dude has constantly got a shit eating grin plastered across his face. Whatever demons he's had in the past, he seems to be at peace with the world now. Getting older will do that to a guy. Good for him.
All this still doesn't change the fact that Pink Floyd would not be a good theme for a pinball machine. As great as their music is, it's not the right style of music for pinball. Great background music for an arcade, just not inside the machine. (pun intended?)
Quoted from RobT:My favorite line from the song is: "We're just two lost souls, swimming in a fish bowl, year after year".
That line was definitely written about Syd Barrett. The wikipedia article talks about Syd's visit to the recording studio while the album was being recorded.