Should I have fought back?

I attended my autistic cousin's 29th birthday celebration, where he exhibited some challenging behaviors. During his gift opening, my mom mentioned that his gift was upstairs but she didn't have the card. Although my aunt reassured her that it was fine, my cousin responded by demanding that she go and get the gift herself. When my mom explained that the gift wasn't in a card, he told her to go upstairs and get it. Everyone laughed, and I made a comment about him saying the same thing last year. However, he responded by telling me to "stay in my place" and that “I’m a child.” This made everyone uncomfortable and his sister defended me by reminding him that I'm an adult and can say whatever I want. Although I was tempted to confront him about his behavior, I chose to hold my tongue and avoid causing a scene. Nonetheless, I still feel upset about the incident and was even tempted to take my gift back.

Should I have fought back?
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