if someone made the intention to fast at night the next day, however he/she woke up late for the Fajr salah, should they continue to fast, or is that fast invalid since they missed the more obligatory salah?
Shaikh Bin Baz rahimahullah said in one of his Fataawa:
وصومه صحيح، إذا كان نوى الصوم صومه صحيح، ولو نام إلى الظهر صومه صحيح، لكن عليه التوبة إلى الله من تساهله،
“His fast is correct if he made the intention to fast. His fast is correct, even if he slept until dhuhr. His fast is correct. However, he repents to Allah for his leniency”
Faisal Ibn Abdul Qaadir Ibn Hassan