I'm sorry to hear that you had to experience that situation. It can be hurtful and difficult when someone makes insensitive comments about a group to which you belong, especially when they are unaware of your identity.
Here are some steps you can consider taking to address the situation:
Stay calm: Take a moment to gather your thoughts and emotions before responding. It's essential to approach the situation with a clear head.
Educate: If you feel comfortable doing so, you can try educating your dad about nonbinary identities. Share your perspective and experiences, helping him understand the diverse range of gender identities and the importance of respecting others' identities.
Choose the right time and place: Find an appropriate moment to talk to your dad in private, where you can have an open and honest conversation without distractions or interruptions.
Express your feelings: Let him know how his comments made you feel without being accusatory. Share your emotions and vulnerability, allowing him to understand the impact of his words.
Share your identity: If you feel safe and ready, you can take this opportunity to share your nonbinary identity with him. It may help him make a more personal connection and empathize with the situation.
Set boundaries: Establish clear boundaries about what kind of language and behavior you find hurtful. Let him know how important it is for you to feel respected and supported.
Seek support: Reach out to friends, family members, or support groups who can provide understanding and encouragement during this time. Sometimes, talking to someone who has gone through a similar experience can be helpful.
Give him time: Changing perspectives and attitudes takes time, so be patient with your dad if he needs it to process and accept new information.
Remember that every situation is unique, and it's essential to prioritize your safety and well-being above all else. If you feel that the conversation might not go well or could potentially put you in an unsafe situation, it's okay to seek support from others first or delay the conversation until you're in a safer environment.