Can he keep me under his health insurance because i have breast cancer? and i have no other health insurance.

I have been with this man for 30 years and married to him for 10 years. In the past few years he has repeatedly cheated with other women and has become an alcholic. And has become abusive toward me and my 17 year old daughter. He is a retired police sargent. This past Christmas I was diagnosed with breast cancer stage 3. I am going threw chemo and am going to be having radiation and surgery soon. I do not work at this time. I really need the health insurance at this time. I need to know will he have to keep me under his insurance because of my breast cancer or will I be dropped? if anyone can help please let me know.