Excessive coughing, and affecting voice..???

Patient: My mother is 88. A very petite women, weighing 98 lbs..uses a walker, and doing well, except for one problem. She has coughing spells, and she has alot of flem in her throat.I feel bad for her because i’m sure she gets very tired from all of the coughing..She is allergic to dairy products..She thinks maybe chocolate is a factor also..When the weather changes, especially when the wind is blowing pollen around, she can hardly talk..Please help we to help my mom..she is not a smoker and never has been..