Praise be to Allah.
The best is for him to go straight to ‘Arafah, because this day is the day of ‘Arafah, not the day of tawaaf. The man who came to the Prophet (blessings and peace of Allah be upon him) and prayed Fajr with him in Muzdalifah – whose name was ‘Urwah ibn al-Mudarris – came from the mountains of Tayy’, from Haa’il, and happened to come to the Prophet (blessings and peace of Allah be upon him) when he was praying Fajr in Muzdalifah, and said: O Messenger of Allah, I have exhausted myself and worn out my mount, and I did not omit any mountain but I stopped at it; have I attained anything of Hajj? The Prophet (blessings and peace of Allah be upon him) said to him: “Whoever offers this prayer of ours, and stands with us until we move on, and halted at ‘Arafah before that, by night or by day, has completed his Hajj and completed the rites prescribed for him.” He did not say that he had done tawaaf al-qudoom; based on that, if you reach Makkah on the day of ‘Arafah, then you should go straight to ‘Arafah. End quote.
Majmoo‘ Fataawa Ibn ‘Uthaymeen (23/22)