Welcome to HCM,
As she passes black stools ie there is some bleeding from some part of gastro intestinal tract.
She is having passing of blood in cough
In this situation she requires evaluation of her case.
She requires few investigations,
1,Stool for occult blood.
2, Routine blood testing for clotting time, Bleeding time
, platelet count
and other routine blood check up.
It is better to consult Physician and get her examined. After all reports he will diagnose her condition and will go for treatment accordingly.
Ok and bye.