What was going on wasn't just spiritual, though. Heart attacks are sudden, and cause friends and family to stop in their tracks and attend to the emergency. Who knows, she might have had plans to go out of town, or plans for him to be in a wedding. Or maybe she had tried talking him into assisted care housing and he'd refused. She might have been angry with him, or at the situation in general, but knew it wasn't appropriate to express it to a heart patient, so she took it out on others.
It sounded like she wanted sympathy for what she was going through, but knew that he would be the only recipient. She was facing the possibility of losing him at any moment. Things would inevitably rush through her head -- will she have to clean out the house, will she need to invite him to live with her family, who else does she need to inform... a lot of life gets shaken.
But yes, the fear of doing things spiritually wrong, or frustration with God for not answering immediately, or arrogance over Christians who "just didn't know how it's done," or extra demonic influence... who knows, all of the above? And more.
Glad she calmed down.