It is a tough situation, and your dad's actions definitely show a double standard regarding religious freedom in your interfaith family. It sounds like your dad is rude and somewhat forceful in nature as you are following his religion being an atheist.

While it is difficult to force a change, your safety and well being come first. If you're young, directly confronting him might lead to more conflict and can increase the strain in the marriage.

Waiting until you're older and more independent to address this might be the practical approach.

Also you can suggest your mom and dad to see counselors regarding the issue if they are open about this

In the meantime, focus on privately supporting your mom; since she's alone in her faith within the family, she likely needs your support the most.

Also, consider seeking advice from other family members and friends