Visiting the sick - Bikur Cholim - is the type of Mitzvah that often/usually cannot be done by others (since every person potentially makes a difference), and therefore one has an obligation to do so even if one could be using the time to learn Torah.
The parameters of that can be asked separately.
My question is: What about if the Bikur Cholim causes the Choleh to stop learning?
e.g., one walks into the ward and the Choleh is learning and doesn't notice one's entry.
May one interrupt them? Should one?
Or should one wait until he takes a pause?
Can one leave (if pressed for time) without having been noticed?
In other words: May I cause the Choleh to do Bitul Torah in order for me to do the Mitzvah?
I'm assuming this question only applies to a Choleh, as a Cholah doesn't have the same obligation of continuous Torah-study.