Dear Sajah, it is tough being a parent and treating your own children especially for something serious. If it is Pertussis, I would get the bathroom really steamy and put a washcloth on the floor of the shower with a 1-3 gtt of EO of lavender and Oregano. Bring your son into the room with a cozy pillow and blanket and breathe for 15 minutes. You can do this twice per day. Internally most of the herbs you listed are not herbs I prefer to use for 7 month olds but I would make the following tincture formula, Elecampane 1 part, Mullein - 2 parts, Wild Cherry bark - 1 part, Pleurisy root- 1/2 part, Licorice 1/2 part, Sundew 1 gtt. I hope this helps