Let me play devil's advocate...
Trust me, far worse things will happen in your lifetime than your fish dying. My mom actually told me once that the reason she gave me pets would be so I would have to cope with death and disappointment--it's a part of life.
geeze... you dont have to be so rude! just cause you dont get attached to a fish doesnt mean its wrong when other people do! have some consideration! it sounds like she had this fish for a long time, so that is reason for her to be upset that it might be dying.
i had a fish i was kinda attached to cause it wasnt a normal fish... it would like come to the top of the bowl and like say hi to me and bite my finger and stuff... it was cute, so i liked it! it commited suicide and i was upset, not very upset cause i have only had it like 6months... so yeah! it happens!