I don't understand what is happening

Hello I am new here. Eight days ago my Mum received a diagnosis of incurable kidney cancer. She had been under the urologists at a local hospital for four years for suspected kidney stones. She was asymptomatic and they were found when having investigations for another problem and the urologists decided not to treat them as they will large but not causing any problems. They wanted to keep her under review and she has had scans every year with no change reported. In May she had a t i a and a few months later the symptoms she had suggested to me that she may be having a second one. I called an ambulance but during the tests that followed her brain scan was normal but on examination she had Tenderness in her tummy area and a scan revealed a mass behind the stones. After further scans we saw the urologists for the results and they told us eight days ago that mom had terminal kidney cancer and the stones could be calcified tumors. The cancer had spread to her adrenal gland and she had abnormal lymph nodes. Since then she has deteriorated quickly. She was diagnosed with a UTI as she was delirious confused and her you're in sample confirmed it. By Tuesday this week her legs would not work and we had to call an ambulance as she was deteriorating with suspected pneumonia. She is now on end of life care after a few days of strong antibiotics intravenously. The cannulas all failed and now she is completely unconscious. Could this be the cancer progressing so quickly? Has anyone else come across similar deterioration?