Kidney cancer metastasis

Hi

My dad was diagnosed with kidney cancer, had full nephrectomy. We were told in October that the tumour was relatively small and was stage 2 with no metastasis and clear margins. My dad recovered well from surgery and then in December started to get ill again. He had CT scans and they took biopsies from a lymph node in his neck, as well as abnormal shadows on his spleen. We were told the cancer had spread (lymph and spleen). A week later after an MRI scan, he was also diagnosed with bone mets mid spine. This bone mets hadn’t been picked up on any CT scan. What is even weirder the original kidney cancer was typed as papillary renal cell carcinoma but it had mutated into clear clear at his lymph nodes.