Nedarim 39: Removing 1/60th of Suffering

A mishnah from Daf 38, and the Gemara on it - one who is the subject of someone else's vow swearing off benefit from him. How would this have impact on a visit to the sick, in either direction? It seems an indirect benefit... One possiblity is standing instead of sitting, while visiting. Plus, "benefitting" from fruit during a shemitah year. Also, where in the Torah do we find the mitzvah of visiting the sick? Plus, there's no "measure" to visiting the sick - with several interpretations of what that means.