Double Bogey,
I suspect you are wrong about the relatives wanting to sue anyone. They will have been compensated, at least in the financial sense, some time ago by the various insurers. In any event, the pilot was acting in the course of his employment, and any claims would fall to be met by his employer or their insurers.
Having followed this closely from the outset, I think what the Sheriff has concluded is correct. However, the question which continues to niggle me is why did such an experienced pilot elect to take this risk, which in turn brings me to the question what were the last taskings about. Why did he orbit two motorway junctions? What did the tasking ask him to look for? Was it an emergency, was life at risk? I have absolutely no idea, but the answers to these questions would surely have had a bearing on the pilots likely frame of mind when deciding to take the risk which he did.