I can't imagine why they would use Schedule C for the forgiveness.  He isn't a Sole Proprietor anymore; the business that took out the loan is a corporation, and the forgiveness should be based on that corporation.

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@Kevin1 wrote:

To complicate things, he has only paid himself draws in 2020,

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I'm rather opinionated about this, but I disagree with that statement.  Compensation is required, not optional.  So at least part of what he received is compensation, but he just neglected to withhold taxes and file payroll returns, which are now late and need to be filed.