I hate the winter months with our SWCAH 6yr old...the poor thing has had strep throat, tonsilitis, ear infection, croup (2’xs)...it seems it never ends for her...anyway what i wantedt o suggest is when the coughing fits start, wrap her up in a warm blanket and take her outside for about 5-10 minutes and see if the cold air can alleviate any of the coughing...our pcp suggested this and for us it seems to work. With our daughter, her throat becomes irritated and "expands" and the dr. said she’ll keep coughing over & over if you cant get it to contract...we’ve tried the neubulizer treatments too when she had a coughing fit and it didnt work, the robitusin or the pedia care didnt work so I can relate on where ur coming from...hopes your child gets better...