I get where you're coming from op, I am a bereaved parent too 💐
I understand the desire to say "well you've still got your kids so what are you fucking moaning about", I really do, but over the years I've learned that it's a bit shitty.
Other people are allowed to be sad, or have a moan about different areas of their lives too, even if their sadness isn't as great as yours, it's still valid to them.
She was talking about a totally unrelated thing, and you've invalidated her feelings.
This path is a massive learning curve, and we all get it wrong, get pissed off at things, say things that hurt others, and generally struggle while we settle into whatever this shit new normal is for us.
That's no justification for what she said, however, that was abhorrent. If she is otherwise a good, supportive and kind sister, I think I would talk to her about it and forgive her, assuming she's sorry (I know you say you feel a bit bullied by her, but assume the relationship is generally good as you were away together).I would also avoid drinking for a bit as well, and definitely stop drinking around her.