Thanks for writing your query.
You can continue giving her mucinex
as this will help to cough
out the sputum.
Steam inhalation will also be beneficial in this.
You can add antihistaminic like fenofexadine
120 mg once day to decrease the irritating cough.
Pain in abdomen can be due to muscle pull of the abdomen during severe bouts of cough.
Hot fomentation will help in relaxing the strained muscles.
It seems that your wife is lying in one position for long. The bruises can be due to pressure sores
resulting from lying in one position for long periods. Encourage her to change her position/posture to avoid them. Also physiotheray can cure these pressure sores, if present.
Urgent medical attention and examination/investigations are needed as her blood pressure is on the lower side and she is having tachycardia(increased heart rate
I hope this is helpful to you.