As far as the IRS is concerned, income reported in box 7 of a 1099-MISC is self-employment income earned by the recipient while "in business" for themselves. Also, it's important to clarify here that it's not "our" business. It's "his" business. Only his SSN is on the 1099-MISC.
"He doesn't have a business. "
Just to clarify here, if the income is reported in box 7 of the 1099-MISC, then regardless of what you and I say, he did have a business in 2017.
"if he materially participated"
If he was the one that performed physical labor (such as lecturing or teaching) then there's no question that he did "in fact" materially participate.
"He has taught a class at this convention before"
That would provide further justification in the IRS's favor that he is self-employed since he has been paid for teaching at this convention on a recurring basis. Is the income reported in some box other than box 7 par chance?
