EF 20 % isn’t good at all. I am not a dr so I will not try to comment on the rest. Best you can do is fallow all her doctor was advising. Do not worry, because that making everything even worst.
When I had (8 years ago) 20% was very upset, but was beating it, all went normal less than a year later.
You must consider that: for more people won’t, also her high age is a factor. I was 57.Even if would go up to 35% she will feel much better.
So keep all she was told, pills, diet etc.. for beginning you can help with (and not all doctor points that as a MUST) is a very low sodium diet, no more than 1600 mg per day.Maximum 2000....Best to eat 4 times a day ...and one meal can not have more than 400 mg. Remember all food has sodium naturally. She or her caregiver must calculate the sodium in all food she is eating. First it is hard then became a routine.
My BEST to her!