In Elton John's Levon who is Alvin Tostig?

Alvin Tostig is Levon's father; he is the grandfather of Jesus (the one who blows up balloons up). As far as I can tell, it's one of those "series of sounds that fits the music" names; no real person, just a good sound that fits the meter and length of the space in the song. FYI - the use of the name Levon is supposedly due to Taupin's and John's admiration for Levon Helm, drummer for The Band.