<human>: I think that my sibling's behavior toward our mother can be classed as "emotional abuse" but I'm not sure.  Wanting some input.

The main incident I'm thinking of happened a few months ago - my niece might be allergic to nuts (we're not sure yet), and we were all out to dinner.  Dessert came, and my niece was eating some ice cream off my mother's plate.  Someone at the table told my mom not to feed the niece the other dessert because it has nuts in it.  My mom state, right then and there, that she wouldn't and that the niece didn't have any of the dessert with nuts, only some ice cream that was on the plate.  There was no allergic reaction at all, and everything seemed fine.  Fast forward 2 days later, and my sibling has been giving Mom the silent treatment (we each usually talk to her at least once a day, and have since Dad died almost 6 years ago).  Mom asks a completely unrelated question via text, and suddenly gets a volley of angry text messages accusing her of feeding the niece nuts, my mom needs to own up to this mistake, and that my sibling doesn't trust her to watch the kid any more.  

The lynchpins of all this, and what prompted my question here, were two things my sibling said to my mother
1) "You fed [niece] nuts, and [sibling's spouse] saw you.  Any denial on your part means you're calling [sibling's spouse] a liar."
2) "If I find out that you bitched to velvet_time, I'll never trust you again!"

The second point in particular is what made me think this is emotional abuse - it sounds like a classic case of an abuser trying to isolate their victim.  The first statement too, is pretty bad - it shut down the possibility for any kind of rational discussion.  It reminded me of the old "Have you stopped beating your wife?" trick question.  There was no room for "mistaken" -  My mother was left in an impossible-to-win situation.

Can you condense the text into three sentences or less?
<bot>: Is my sibling's black-and-white reasoning and attempted isolation of my mother emotional abuse, or is it just childish?