Hello and hope you are doing well.
Agree with the previous suggestion that a combination of antibiotics and bronchodilators will help relieve symptoms of COPD. Just check to see if any allergens are triggering his episodes of coughing. This could even be anything like temperature changes. Keep a diary and make a note of his symptoms, this will help to track the allergen and avoid the same. And ask him to do steam inhalations and breathing exercises.
Hope this helped and do keep us posted.
He sounds severely congested. This excess phlegm may be causing his COPD to look worse than it is. That was certainly the case with me.
I have COPD, and suffered the same horrible and exhausting coughing and choking. A good part of the problem was caused by an inhaled steroid. So I stopped taking it and substituted natural anti-inflammatories. That helped.
Some time later, a respiratory therapist noted my congestion and suggested nebulizing with Mucomyst (acetylcysteine). My lung MD put me on that and the congestion disappeared almost overnight. My lungs were clear for the first time in years. All my test results improved. Mucomyst is a mucolytic (mucus thinner).
Now the only medication I take for COPD is Duoneb, Mucomyst, and an over-the-counter anti-histamine. I also take a variety of vitamins, minerals and supplements. in modest amounts.
I almost forgot. If your father has been taking antibiotics or prednisone or inhaled steroids, these can promote the overgrowth of a yeast, usually Candida albicans. This infestation produces mucus.