He assumed Ihram and when he reached Al-Haram, he felt some pain in his head and in all his body, which prevented him from completing his Hajj
Your condition is invalid because it was mistimed. The
time of stipulation is when assuming Ihram (ritual state for Hajj or `Umrah). So, you take the ruling of a Muhsar (pilgrim prevented from completing Hajj or `Umrah) and you are charged with a sacrifice to be slaughtered where you were prevented from completing the `Umrah (lesser pilgrimage) and distributed among the poor in that place. (Part No. 10; Page No. 390) You are obliged to avoid the prohibitions of Ihram until you slaughter the mentioned Hady (sacrificial animal offered by pilgrims).May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.