Chronic Obstructive Pulmonary Disease (COPD): This is a common condition in elderly males, especially those with a history of smoking. The productive cough at night can be due to increased mucus production and airway obstruction.

Chronic Bronchitis: Similar to COPD, chronic bronchitis is characterized by a chronic productive cough, often worse at night, and is commonly seen in smokers or those with a history of smoking.
Asthma: Although more commonly associated with wheezing, asthma can present with a productive cough, especially at night, due to airway inflammation and constriction.
Gastroesophageal Reflux Disease (GERD): GERD can cause a chronic cough, which may be more pronounced at night due to lying down, allowing stomach acid to flow more easily into the esophagus and irritate the airways.
Heart Failure: Congestive heart failure can lead to a productive cough at night due to pulmonary congestion, where fluid accumulates in the lungs.

Pneumonia: Although less likely without other symptoms like fever or acute onset, pneumonia is a critical diagnosis not to miss, as it can be life-threatening, especially in the elderly.
Lung Cancer: A new or changing cough, especially in a smoker or former smoker, warrants investigation for lung cancer, as early detection can significantly impact prognosis.
Pulmonary Embolism: While often presenting with sudden onset of dyspnea or chest pain, a pulmonary embolism can sometimes cause a cough and must be considered due to its high mortality rate if untreated.

Cystic Fibrosis: Although typically diagnosed in childhood, some cases of cystic fibrosis may not be diagnosed until adulthood, presenting with chronic productive cough among other symptoms.
Bronchiectasis: A condition characterized by damaged, dilated airways, leading to chronic cough and sputum production, which can be considered if other diagnoses are ruled out.
Sarcoidosis: An autoimmune disease that can affect the lungs, causing cough and other respiratory symptoms, though it's less common in the elderly population.