Interesting question. There may be some nuance I'm not aware of, but to my ears passing away and passing on are largely identical euphemisms for death. If I r

Interesting question. There may be some nuance I'm not aware of, but to my ears passing away and passing on are largely identical euphemisms for death. If I really were to stretch I'd say passing on sounds a bit more like something applied to a person who was actively engaged in life, whereas passing away sounds a bit more like what might be said of an elderly person who has already somewhat detached from the world even before death, but that's pretty tenuous.