I find the question a bit confusing. If they already issued a W2, yes, they treated the person as a household employee. But box 10 is for a (potentially) taxable benefit received for the care of the W2 recipient's dependent. It's not for doing the work, but for incurring the cost that an employer then offset with a fringe benefit payment amount. Box 1 is where income paid to the W2 recipient would be listed, and not also Box 10 if the W2 recipient is not the box 10 beneficiary and isn't the one incurring the expense of care.