Nonrenewing bc of family member's business?? This is a first for me....

Nonrenewing bc of family member's business?? This is a first for me. Electrician's Workers Comp nonrenewing bc of mom's company existing. Mom's company is not connected to insured's at all- he's a electrician, she has a concrete plant. Different addresses. Different LLC members. Insured is in a building with 12 other companies, a few of which are family members, including dad's GC company, but carrier didn't take issue with that. What gives??