Yep, Mr Crimson - Why? Do you want more people to pass onto the other side or something?
Seriously, I'm sure the song can be applied to anyone close to you that passes away. But Macc is correct about the main inspiration of the song.
Another personal song is 'Iron Wheels' from the 'Forever Free' album. It is about Biff's father. I still think it should be a song played live by the band.
If you're looking for a song that is a dedication to more famous people that have passed on, 'Requiem' from the 'Solid Ball' album is a nice one. It is also on Graham Oliver's solo album 'End Of An Era' re-titled as 'Born To Rock 'n' Roll'. It's dedicated to the likes of Hendrix, Bonn Scott and Keith Moon.