HI, thanks for using healthcare magic
Severe infections can result in delirium
in any person including the elderly. It would be more common in persons with impaired immune system such as children, the elderly or those on medications or with illnesses associated with an altered immune response.
The history of enlarged heart
, if it is not working well, would contribute to her fatigue
and shortness of breath
If she is slowly improving, as you are indicating, then you can consider monitoring her for now
I hope this helps