That's a sad story izzybiz.
I understand your sister's motivation but IMO it was a bit naive of her to post about such emotive issues on a first post.
(Disclaimer; absolutely NOT looking for a discussion about vaccination with my next comment.)
My DD1 reacted terribly badly to her baby jabs and they made her extremely ill. I found MN when I was looking for advice about her health problems. It would NOT have been a good idea for me to make my first post saying my DD had been vaccine damaged and warning others about the possible dangers of vaccines. I would have been called a troll and no doubt been flamed.
I think my first thread was in camping asking for advice about ground sheets.
I have since stuck my oar into the vaccine debate and spoken about my DD but I certainly didn't in my first post.
This is the internet, there is a non written etiquette which you don't have to abide by but it is there for a reason.
Unfortunately on MN we do get trolls and journalists (and sometimes people who get off on talking about personal/sensitive subjects).
I agree that shouting troll all the time is annoying but people who think they can start off their time on MN by posting about something sensitive and not come under suspicion are being a bit naive. Sorry.