Open Question: Is it legal for my dad to discontinue health insurance for his kids?

My dad has health and dental insurance from his work, and we all are covered under it. I have 3 siblings ages 8,13, and 15 (I am 20) My mom is also on his insurance. My dad is bi-polar, and has issues with anger (he refuses to seek treatment) He is very emotionally abusive, and threatens to not buy food. He controls all of my mom's income. He's really hard to live with. So, this morning his