You are required to take account of them to the extent laid down by company law and by any shareholders' agreement.
As far as general company law is concerned, the two key requirements are that the directors should promote the long-term success of the company, and that shareholders should be treated equitably. Using the company for the private benefit of the family is therefore prohibited, though in practice it can be very difficult for a minority shareholder to do anything about it.
A shareholders' agreement may grant minority shareholders additional rights. For example, a minority shareholder might be entitled to nominate one or more directors to the board. This would at least ensure that the minority shareholder could express their views at board meetings.
