Docs don’t have time to speak with each other regarding shared care of a patient due to time limitations, too many patients, etc. PSA does not directly check for cancer but for prostate size. In the olden days they digitally checked it and verified with a PSA and now only PSA. Cancer diagnosis is by biopsy. Injectable weight loss drug sounds like one of those new one that cost a ton, treats both DM and weight and has terrible side effects. At 79 is that what your dad wants?