Recent development: The doctor says this may have been triggered by a recent fall. Dad is starting Zoloft, but we need to keep him safe until it takes effect, which is about 4 weeks. My sisters and I provide 24/7 care for him but, he called 911 on his own last night and told the paramedics he wanted to kill himself. There are no firearms in his home, but we want to secure sharp objects and chemicals. His medications are already secured.
Is the prescribing doctor a psychiatrist, better yet a geriatric psychiatrist?
I think you should be willing to hear with both ears whatever is recommended. If a dr feels a patient needs inpatient care to get the patient beyond the point of wanting to take his own life, then isn't that what you would want? The dr has a responsibility to do what he thinks is right for your father. You've just written that you and your sister were with him and he called for help. It usually takes about 30 days for a depression med to work.
I'm surprised a fall can trigger these types of thoughts. I would consider getting another medical opinion. Did he start any other new meds after the fall? Could these thoughts be one of the side effects his medication?