I'm not sure what you're trying to say by "Let that poor soul..."

We aren't in a position to "let" or "not let" this person do anything with their own body and medical treatment. We are random people on the Internet. I get feeling the urge to offer unsolicited advice even though I don't necessarily agree with doing it, but the mindset that one is in any kind of position to "let" this complete stranger do something to themselves seems a little egotistical. Calling them a "poor soul" just reinforces that by adding condescension on top.