Regarding lymph node involvement, I think it depends how close they are to the tumor.
As far as I know, regional (local) lymph nodes do not preclude surgery.
Distant lymph nodes is a different matter. Involvement of distant lymph nodes is considered to be metastatic disease. Metastatic disease typically means that you cannot have surgery.
I don't know where the boundary lies between local and distant nodes.
Please keep in mind, I'm not a doctor. I'm a caregiver just like you.
Best of luck to your son.