Dads Coughing. Is there anything to help it?

My dad finished his 1st round of Chemo about a month ago. He was feeling great after stopping the Chemo for about a week. He seemed to have energy and was finally not so sick. We had good results when we went back for his check up and the chemo shrunk the tumor in his neck to almost nothing and shrunk the tumors in his lymph nodes.
Now his coughing is pretty bad. He has a difficult time and gets winded when he goes up and down my stairs in my house. The coughing is so bad that it makes him throw up sometimes. Its so hard to hear him. I dont know what I can do for him.
Does anyone know if there are any treatments to help him with this nasty coughing? At least to give him relief for a while?