Hazrat Shaikh Moulana Muhammad Zakariyya (rahmatullahi ‘alaih) once mentioned the following to a person who had travelled to the holy city of Madinah Munawwarah:
If at any time, you are unable to complete your zikr or other ma’moolaat due to illness, then there is no need to feel grieved over this. When one is sick, one is regarded as excused and one receives concession. Hence, when you are not well, then you should do whatever you are able to do of the ma’moolaat.
Nevertheless, as for presenting yourself at the Rowdhah Mubaarak for salaam, then as much as your health and strength permit you, you should try to continue going to present salaam, as this ibaadah is a substitute for carrying out many different types of zikr (and ibaadaat).
You wrote to me mentioning that you sit near the Rowdhah Mubaarak and complete different types of ma’moolaat, at times you engage in zikr and at other times you engage in dua, then there is no problem in this, and there is no need for you to become worried. You should engage in whichever type of ibaadah your heart feels inclined to doing (while you are at the Rowdhah Mubaarak in the musjid). However, from all the various ibaadaat, the most preferred ibaadah at the Rowdhah Mubaarak is to send durood and salaam.
Undoubtedly, to spend even a few moments at the Rowdhah Mubaarak is so great and virtuous that it is greater than remaining in the company of all the Awliyaa. You should regard this ibaadah to be extremely important and most valuable.
Please continue to convey salaam to Rasulullah (sallallahu ‘alaihi wasallam) on behalf of this unworthy servant, however when doing so, ensure that your focus and attention is not directed towards me, but rather, your complete attention and entire focus is directed towards Rasulullah (sallallahu ‘alaihi wasallam) at all times.
(Qutbul Aqtaab Hazrat Sheikhul Hadith Moulana Muhammad Zakariyya (rahmatullahi ‘alaih) pg. 385-386)