My son due to some timing misunderstanding drinks water at 4:38 today. Does his fast still valid?
Review your Time Table for Fajr you are following, and see if it utilizes 5 min or 10 min of imsak for that day. Accordingly, assess if your son has eaten in the actual Fajr time. If he did, then his fast would be invalid, and he will need to keep a qadha’ (no kaffarah). If it was before the actual fajr begin time, then the fast would be valid.
And Allah Ta’āla Knows Best
Mufti Faisal al-Mahmudi