Stipulating a Condition is Sunnah for whoever fears
Question:
If the person who has assumed Ihram fears that he will not be able to perform his rites due to illness or fear (of something preventing him), what should he do?
Answer:
When he assumes Ihram he should say: “If something prevents me, then my place of removing Ihram is wherever You stop me.” If the person fears something of the things that would prevent him from completing the Hajj, like illness, then the Sunnah is that he makes the stipulation. This is due to what is confirmed from the Prophet sallAllaahu `alayhi wa sallam that he ordered Dhuba’ah bint Az-Zubair bin ‘Abdul-Muttalib to do so when she complained to him that she was sick.
Source :
Shaykh `Abdul-`Azeez Bin Baz
Fatawa Islamiyah, vol.4, p.42, DARUSSALAM