On those occasions, I have been moved to tears merely by someone taking my left hand. There is remarkable power in such moments, and unaccustomed to sensation, my hand doesn't anticipate the warmth or the power it sometimes finds in that touch.
It's clear that my hand has little to do with it. Had my eyes been closed, I would not have known even that my hand was being touched - much less have perceived the warmth offered from a healthier hand. My mind is supplying that perception in the absence of sensation.
We have wrestled with mind-body distinctions for many centuries, certainly since Descartes 400 years ago, but you can find early threads of that discussion in Classical Greek thought. Are mind and body separate things? If so, does mind influence body or vice versa? Or both? If they're separate, how do they stay synchronized? What if they don't? Maybe mind is simply what the brain does? Let me know when you figure it out.
At any rate, on these occasions my mind is doing for me what my body cannot. It supplies the perception of warmth which is amplified by the knowledge that there is another who cares. The perception is one of psychological as well as physical warmth. Ultimately I am profoundly moved by that.