Is the fast of one who drank water at the time of the Fajr Adhan out of necessity—fearing choking due to stomach surgery—valid, or must he make up this day?

If a fasting person drinks one or two minutes after the Fajr adhan (definition), their fast is valid, and they do not need to make it up. This is because the current adhan relies on timings, as it is difficult to sight Fajr due to the abundance of lights, and the calendar is often a few minutes ahead as a precaution. Ibn Uthaymeen and Al-Fawzan mentioned that eating and drinking a little after the adhan does not invalidate the fast unless dawn has clearly appeared.