The man in this prompt is living in an unusual place.
To start with I have been researching geography a lot lately and one of the things that comes up more frequently than you would think is that solitary mountains are not normal. Not normal doesn’t mean they don’t exist, but they definitely aren’t common. Usually they are smaller mountains near them or larger, no reason to assume every mountain is the largest one around, since obviously that’s not the case.
The next thing is that he lives in old ruins. Honestly, that those ruins exist makes some sense to me. If you really had a solitary mountain, there are multiple reasons why someone might build on it. The first one that comes to mind is defensibly. A solitary mountain with no other mountains around it absolutely has the high ground. If you set a watch, you will know long before an enemy arrives that they are coming. On top of that, with how unsual they are I can definitely see someone proclaiming them to be a holy spot.
It says that he lives there, but it doesn’t say if he lives there with anyone. It is a ruin, so it probably isn’t home to a lot of people and being a mountain there is certainly the potential it to be cold for the air to be thin. When I picture this man, I see him living there with his dog, a mid to large size dog with a nice thick coat. Who, if anyone, do you see living with him?