The problem with all this is, we dont know if he was out for a walk or if he was heading home cos he wasnt feeling too well. There's a huge difference and it changes the whole dynamics of the mystery.
Even if he was perfectly fine and just out for a walk, as many of us do on holidays, how many of us at that age would decide to scale a mountain that even the locals never go up. Who would go off the beaten track in midday sun, dressed in trainers with only an umbrella.
I urge anyone to take a look at a map or pics of the area where they're searching. Its pretty high and unpassable if ill equipped.