Stumped by a rude doctor who will not acknowledge caregiver questions. Is it possible to transfer to a different doctor when a patient is on a specialized drug that is only administered by the doctor's office?

Has anyone had to transfer a parent to a different doctors office while they were on Zytiga? Is it possible to transfer to a different doctors office when a patient is on a drug like Zytiga that is so specialized, it's only administered by the doctors office? Dad's prostate cancer has progressed, it's spread to his bones, he was referred to another urology office who could administer the Zytiga. Everything is good with the office, but the doctor. I've gone with dad on appointments even before he really needed me, because he asked. Dad is intelligent but poorly educated, has always had a hard time understanding medical terminology, couldn't fill out his paperwork, says yes to everything in a doctors office, even in regard to when he's asked about symptoms. Can't pronounce prostate. Dad has a minor speech issue, born that way. I've been his caregiver for five years, he's 83, hard of hearing, has difficulty walking, we use a wheel chair. This doctor does not acknowledge me as a caregiver, does not want me to ask questions, does not talk to dad about side effects to watch out for. The doctor has one chair pulled to his desk for the patient and three chairs on the side against the wall always. I ask questions, doc gets angry, like I've inconvenienced him and I'm taking up good air in his office by being there. Doctor has been asked about walking, why doesn't he walk? Dad tells him in his way, doctor doesn't understand or listen. Yesterday dad was asked about his dentures. I said "dentures?". The man leaned up on his desk from a sitting position, put his fists on his desk, leaned over wide eyed and glared me down, took a moderate scolding/correcting stance towards me because I asked why do dentures matter with prostate cancer. My dad leaned back in his wheelchair, and in all honesty the behavior frightened me. I've noticed this doctor was extremely tense from the first appointment. I want to find another urology office closer to home, see if they can request dads medical records, schedule an appointment and see if they can get his zytiga in time without a gap in treatment. I don't want to cause conflict with the current office either, but I feel this doctor will not work well with us when dad reaches a point he needs Xofigo (Radium 223) and he's radioactive and may need to be hospitalized for that reason. We need a doctor who works well with the caregiver as this progresses. Any ideas, or similar experiences?