My brother in law has renal kidney cancer that has spread to his lymph nodes and bones, what is his life expectancy?

Difficult to predict. Each individual case is unique & predictions are very difficult. Factors such as tumor histology, size, & prior surgery have an impact on prognosis. Data from large series show that median survival for patients with stage IV disease is 16-20 months, and the 5 year survival rate is less than 10% for patients with distant metastases. Many new drugs have been developed that may improve survival.