Laurie,
Is your husband being treated at a major Comprehensive Cancer Center (CCC)?

It is very rare these days for a CCC not to find a primary and bilateral lymph nodes tumors from a true unknown or multiple unknowns seems very unusual.

There is a lot of extra and larger areas of irradiation to endure when the primary can not be found, so a good CCC does a lot of extra work looking, surgical scoping, special hi-res CT scans, maximized slice CT/PET scans, lots of punch biopsies, numerous doctors/surgeons looking, etc.. before giving up.

Unknowns often suffer higher morbidity issues from the excessive radiation