He does have hardening of the arteries...in his aorta - part of the heart -one of the big tubes that carries oxygenated blood from the heart- when there is a build up or calcification of the aorta - it is thinner on the inside - and doesn't have the stretch - that it should to accommodate proper blood flow.

The same can be said for his carotid - an artery that brings blood to he brain - you have two - thinning, or blockage of these arteries can cause a stroke / insufficient blood flow to the brain - if you place your fingers under your chin beside your wind pipe you can feel a pulse - this is your carotid artery. Subclavian runs under your clavicle - it's the first bone your fingers hit if you run your fingers down your throat - also he common aortic arteries are arteries that bring blood to various locations in his body - ultimately - they all connect to the heart - he is likely going to one of a number of treatments - possibly blood thinners, diet change, and depending on how severe maybe a bypass of some sort...

Good luck! Hope this helps!