He did the farewell tawaaf at night but was not able to leave Makkah until the following morning

Praise be to Allah.

What is prescribed is that the pilgrim's farewell tawaaf should be done when he is leaving Makkah al-Mukarramah, because of the hadeeth of Ibn ‘Abbaas, the authenticity of which is agreed upon: people were commanded that the last thing they should do is to circumambulate the House, but an exception was made for menstruating women. So long as you did this tawaaf with the intention of leaving at night, but you were not able to do so until the following morning, there is no blame on you for that, in sha Allah. But if you had repeated tawaaf at the time of your departure, that would have been more on the safe side. 

And Allah is the source of strength; may Allah send blessings and peace upon our Prophet Muhammad and his family and Companions. End quote. 

Standing Committee for Academic Research and Issuing Fatwas. 

Shaykh ‘Abd al-‘Azeez ibn ‘Abd-Allaah ibn Baaz, Shaykh ‘Abd al-Razzaaq ‘Afeefi, Shaykh ‘Abd-Allaah ibn Qa’ood 

Fataawa al-Lajnah al-Daa’imah, 11/303