There is no specific du’a to be said at the time of suhur. What is prescribed is to say Bismillah at the beginning and to praise Him when one stops eating, as should be done at every meal.

It is recommended to delay suhur and it is not recommended to stop eating and drinking a while before Fajr. Allah has permitted those who intend to fast to eat and drink until they are certain that dawn has come.

If a doctor cannot break his fast with fresh or dried dates, then he can break his fast with water. If he cannot, then it is sufficient for him to have the intention of breaking the fast.

Du`a for breaking fast should be made before iftar, at Maghrib, because this combines weakness and humility, and because he is still fasting.