السلام عليكم ورحمة الله وبركاته
1. Once someone has made the intention for an obligatory qada fast during the night and does not change or revoke the intention prior to true dawn (fajr sadiq) then it becomes obligatory for them to complete the fast.
2. Sleep after forming the intention does not invalidate the intention.
3. Accordingly, it is impermissible for him to break his fast once the day has commenced. This view represents the official and strongest position in the Shafi’i school.
4. An alternative and weaker view exists within the Shafi’i school, allowing for the said person to break his fast even after the commencement of the day.
5. This alternative view is contingent on the following conditions:
5.1. The obligatory qada fast must be of a nature that allows for its postponement. For instance, a qada fast that can be delayed is when the person missed fasting due to a valid excuse, such as illness.
5.2. There must be sufficient time available for the individual to make up the missed fast before the arrival of the next Ramadan.
والله تعالى أعلم
And Allah knows best.
النصوص المستندة إليها
تحفة المحتاج جــــ ٣ صــــ ٦٠٦-٦٠٧
ويشترط لفرضه كرمضان أداء و قضاء و كفارة و منذور وصوم استسقاء أمر به الإمام (تبييت) اي إيقاع النية لي الً اي فيما بين غروب الشمس وطلوع الفجر اه