Well, it is possible this is pneumonia- Obviously without examining him I would be a fool to be definitive one way or another- Pneumonia is best diagnosed by examining someone's chest and checking an X ray- His symptoms are more suggestive of a virus, but that is the best I can say online, as I am sure you understand. That is why I am being more cautious in saying a chest X ray and seeing a doctor is needed if he does not improve in a couple days.
Yes, this can be contagious- particularly if it is a virus- this is spread by close contact and airborne droplets. I would advise frequent hand washing after you have been around him and avoid his direct droplet secretions.
As far as OTC medication, I personally use the store brand , generic (i.e. cheaper) form of Dayquil and Nyquil. They all work equally well and control symptoms. Check the bottle for something that controls cough, and has a decongestant. The bottle will explain how to take it.
Xopenex likely will not help much unless he has wheezing. It does not help in most uncomplicated influenza cases.
This would not be expected to effect heart function, blood pressure, or pulse or oxygen unless he develops a secondary complication- A small number of people after 'the flu" then come down with pneumonia, which can then cause sepsis and complications- Again one would be concerned if symptoms worsen, his sputum does not settle down, fevers continue to rise, he develops shortness of breath, or chest pain. All of these again would be reasons to see a doctor.