And therein lies the difficulties of trying to combat tax avoidance from a moral perspective.
Between the extremes of tax avoidance, there is a feck of a lot of grey area. In the case of DC's dad, and on the basis of the information known, I would suggest it is an abusive and artificial arrangement and would possibly fall under the general anti-abuse provisions so very much a darker shade of grey.
However, it was put into place long before these provisions were even thought of and in a very different climate. Tax as a moral duty is a relatively new phenomenon and getting the wider public to support this is very near political genius.
If DC is not a controlling party, there is not a great deal he can do about it - beneficiary or not so, twat though he may be, I don't think we can pin this on him.
And you don't have to go very far before the darker shades of grey of the aggressive avoidance schemes start turning into prudent financial planning...simply acting through a limited company can save £'000's in tax and national insurance. This is commonly accepted practice, and in many cases is done purely to minimise tax liabilities (although there are also often commercial reasons to do so).
That's the problem; where do you draw the line?