What great age your little pooch has reached! I can understand your concerns about the heat as it can be quite a danger to the elderly in general.
When compared to humans, dogs are not as efficient as keeping cool. Whilst we have sweat gland all over our body to allow evaporative cooling over a great area, dogs have very few sweat glands and most of them are located on their paw pads (not the best spot to cool down from!)
Despite their lack of sweat glands dogs have developed a clever means of heat exchange through panting and breathing whereby evaporation occurs on the moist lining of the lungs and in the mouth. Cooling by these means is dehydrating so maintaining a plentiful supply of fresh water is perfect!
Vasodilation (dilation of the tiny blood vessels close to the skins surface) also helps to keep a dog cool. For this reason you’re certainly helping your little friend by keeping his coat short and providing a wet towel or ice pack on particularly hot days.
Apart from this, maintaining optimum health and controlling any painful conditions is also crucial. Heart disease can be managed, if necessary, with medication prescribed by your veterinarian. Osteoarthritis can immobilise pets and prevent them from seeking shade or drinking on hot days so ensure this is also taken care of by your veterinarian.