When do you call in Hospice?

My Dad has prostate cancer, copd, emphysema. His hips always in pain Dr thinks the cancer may have spread. Dads 89 he doesn't know he has cancer . My mom had us not tell him when she was alive. For over a month he's had a headache each morning. He's 6ft down to 120 lbs. He's weak now but Dr doesn't want to call hospice in. I feel he needs it for oxygen and pain. Every month he gets pneumonia. I take him tomorrow because it hurts when breathing. I don't know what to do I love my Dad and I don't want him to suffer because Dr want release him.