It is definitely 'fixable' however that all depends on how much the owner is willing to pay. As it rolled over, it most likely needs a new monocoque, as well as front and read subframes. In addition to that the fact that this was bespoke (part of McLaren Bespoke Project 8) and that it had a High Downforce kit (which is around $250,000-$500,000 not too sure) it is definitely able to be fixed, however at a cost. Rowan Atkinson payed I believe £910,000 to repair his McLaren F1 (2011 Accident). If I'm not mistaken, the monocoque did not need to be replaced, only the rear subframe and the body panels. Rowan Atkinson did not have the High Downforce Kit on his car so the price to replace the bodywork would have considerably less. I do not know for certain but I have heard the figure estimated to be £1,300,000-£1,500,000 to completely fix this car.