Her voice and cough sound more like smokers cough. It is raspy and low
I just thought of something...
A few weeks ago she was obviously being directed by a voice coach to speak softly, slowly, condescendingly (I added that one), grandmotherly.
She did that in several venues for about 2 weeks.
That was all she could stand, she couldn’t stand any more and reverted to her normal Screech voice.
It seems to coughing fits could be related to her Screech voice. It could strain her vocal cords and throat muscles, leading to irritation that results in coughing.
Resolution: Stop with the SCREECHING.