Good day Sir and Job well done.

My boss is schedule for B-visa interview next week. He had traveled to South Africa with his old passport and which he indicated in his DS160 form but the issue now is that he could not find his old passport which carries the South Africa visa, though he has the soft copy of the visa.
my question is can he attend the interview without the old passport or should he fill a new form and declare it missing in the form?

your quick response will be highly appreciated.