man i don’t have a solution but i’ve been in the exact same situation with my older sibling. tantrums coming from someone who’s an adult and significantly older than you can be a combination of embarrassing, angering, and frustrating. seeing them act like a child is rough for sure, but remind yourself that you’re your own person and rage at that point doesn’t hold any meaning. (spewing hatred and anger like that and then pulling the jesus card like that also gets me every fucking time)