Does it not strike you, as it does me, that a poor old soul can either have the emphasis on poor or on old, and if we leave old out entirely, anyone we describe as a poor soul has a hard life, or at least a hard time of things right now.
The expression in itself is surely a measure of the speaker's concern for the other person, not a snide comment on either their poverty or age.
Are we not all sligthly guilty of taken offence, where none is intended when we hear or read the words "old" or "elderly" irrespective of how and when they are used?
At 72 I am an old woman, by any and all accounts - I have not menstruated for 52 years, which surely is one sign of old age?
My hair is turning grey - another sign, I have a cataract forming in my left eye and I am a widow. I am also in receipt of state pension and pensions from two unions I belonged to at different points in my working life. So by anyone's standards. anywhere in the world, I am an old woman.
This does not mean I am a poor old soul, or at death's door, but it could mean either of these things.
Sorry, if I am de-railing a light-hearted thread, but I do get so tired of this self-conciousness about age.