What to expect in my husbands diagnoses, he has stage 4 renal cell carcinoma. 2.5 CM tumor on right lung, one in vera cava vein, left kidney out..

Serious situation. From your description, your husband has advanced kidney cancer including at least a solitary lung metastasis. Not sure if you mean he had renal vein involvement on the kidney specimen or whether there is tumor left behind after removal. Next step would be chemotherapy or (less likely) immunotherapy. Not likely a role for radiotherapy. If lung lesion is only remaining site, may be role to remove.
Palliative. Good chemo and radiation may stabilize but unlikely any resections unless a mass begins to cause some local problem.