Voluntary Work - close relative

Have a client who has incurred an overpayment of SDA for as he has explained undertaking voluntary work.  The issue which I wish to clarify is that this work was for his brother, his bother and brothers wife are business owners of a small Limited Company.  My view is that this work would be counted as being for a close relative and therefore could not be counted as being exempt even though it concerns a limited company, is my assumption correct or not.

Look forward to your comments.

GR