The case is under appeal from the UK courts but not the French courts and most EU states have been awarding compensation to pax in accordance with the Sturgeon ruling since Dec 2009: http://eur-lex.europa.eu/LexUriServ/...7J0402:EN:HTML

As a mechanical delay is not covered by the concept of 'extraordinary circumstances' then your relatives are due 600 euros per passenger for the delay.