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?