The diabetic during Ramadhaan

I have a wife who is approximately 85 years of age; She is a Muslimah and in shaa.-Allaah she is from among the good people. During the latter years of her life, she has been afflicted with diabetes and has reached such a state of weakness that she has to be hospitalised and becomes unconscious, and sometimes when she is at home.

Did not make the intention that night to fast the following day

After a man had gone to sleep [one night], the sighting of the moon for the start of Ramadhaan was [officially] announced; [This being the case] he had not made the intention that night to fast [the following day] and [as such] he woke up in the morning and did not fast [that day] since he was unaware of the [official announcement of the] sighting of the moon. So what is obligatory upon him now?

Intention for fasting

Concerning an imaam of a Hanafee masjid who mentioned to his congregation that he has a book in which it mentions – if the intention for the fasts of Ramadhaan are not made before the last appointed time for the ‘Ishaa [prayer] or [even] after it or at the time of suhoor (the pre-dawn meal), then there is no reward for his fast. So is this correct or not?