Lisa,
If I were you, and they don't find your husband's primary, put off the start of Induction Chemo and get to MDA Houston for a comprehensive exam and second opinion.

There are NCCN Guidelines that really should be closely followed when there is the possibility of an Occult(Unknown)Primary and the protocol is significantly different than with known Primaries.

http://oralcancerfoundation.org/treatment/pdf/head-and-neck.pdf (look under Occult Primary)

The protocol you mentioned seems somewhat inconsistent and incomplete. There are many steps to be followed before Chemo.

These days a Major CCC can find the Primary for almost all referred cases.

Some of the most comprehensive studies of true Occult(unknown) Primaries has been done by MDA. Some of their recent work has linked HPV to Occult Primaries. They tend to write the book on many of these things.