What determines a statutory employee? He is 100% commission on all sales.?

Question

His employer pays no expenses. He contributes to company stock program and has a 401k.

Answer 1

The law determines that.  Not all sales jobs are statutory.  His employer will indicate on his W-2 whether he is statutory or not by checking the box in Box 13 or not.  If he disagrees with his employer's determination, he needs to take it up with his employer.