[The Ruling on Passing through Makkah When Coming from al-Madīnah after Hajj]

Answer: If the matter is as described in the question, it is permissible for the man mentioned—so long as he has no intention of ʿUmrah—to pass the miqāt without iḥrām and to enter the Ḥaram without iḥrām, for the following reasons:
1. By analogy with those who have valid excuses for whom the Sunnah granted concessions; what they share in common is the excuse due to which ʿUmrah is burdensome.
2. The Messenger of Allah (May Allah bless him and his family and grant them peace) appointed the mawāqīt “for whoever intends Hajj or ʿUmrah”—so the narration states. Therefore, the one who does not intend Hajj or ʿUmrah, together with an excuse, may pass the mawāqīt without iḥrām even if he enters the inviolable Ḥaram—on account of his excuse.
3. Many scholars—among Ahl al-Bayt (peace be upon them) and others—held that iḥrām is not obligatory except upon one who intends one of the two rites; not upon one who does not intend them, even if he enters the inviolable Ḥaram.
4. There are general evidences supporting what we have stated: “Allah intends for you ease and does not intend for you hardship.” [al-Baqarah:185] “And He has not placed upon you in the religion any difficulty.” [al-Ḥajj:78]
And in the Qurʾān there is what indicates dispensation in many obligations: the concession for the traveler to break the fast during travel and in illness, and the concession to lay down arms in rain, in His saying: “And let them take their precaution and their weapons. Those who disbelieve wish that you would neglect your weapons and your baggage so they could come down upon you in one attack. But there is no blame upon you, if you are troubled by rain or are ill, to lay down your weapons; but take precaution. Indeed, Allah has prepared for the disbelievers a humiliating punishment.” [al-Nisāʾ:102]
The Sunnah has likewise come with many such concessions, including matters in Hajj: waiving Ṭawāf al-Wadāʿ for a menstruating woman; waiving some of the rites of the night of Muzdalifah for the weak among the pilgrims; waiving the overnight stay in Minā for al-ʿAbbās because of supplying water; and likewise for the camel herders, for whom a concession was granted to omit the overnight stay and to stone one day and leave another.
Accordingly, we say: it is permissible to omit iḥrām when passing the miqāt due to an excuse.
Yes: if the excused person omitted iḥrām at the miqāt and then, upon reaching the boundary of the inviolable Ḥaram, felt able to perform ʿUmrah, he should enter iḥrām before entering the Ḥaram. If he knows himself to be unable, it is permissible for him to enter the inviolable Ḥaram and then enter al-Masjid al-Ḥarām—all of this due to the presence of the excuse.
Source : Min Thimār al-ʿIlm wa al-Ḥikmah vol.1