What is the ruling on one who broke their fast for a day in Ramadan due to severe exhaustion, and do they owe a make-up fast and expiation?

Worship must be completed once begun, and it is forbidden to break the fast of a Ramadan make-up day without a valid Shar'i excuse. If a Muslim breaks the fast of a make-up day without an excuse, he incurs sin. The Hadith of Umm Hani’ indicates that breaking an obligatory fast without an excuse harms its doer with sin. If the tiredness is severe exhaustion, making it difficult to continue fasting, then it is a valid Shar'i excuse and incurs no sin. However, if it is ordinary tiredness, it is not considered a permissible excuse for breaking the fast.

A Muslim must repent to Allah and make up the day he broke his fast. No expiation (kaffarah) is required for breaking the fast of a Ramadan make-up day, as expiation is specifically for those who violated the sanctity of Ramadan itself.