have you tried honey? maybe with a little lemon added. I try not to give my kids typical cough medicines, but I do like the brand Hylands, which is a homeopathic brand. They have a Nighttime Cough & Mucus formula that we've been using. I've also heard that using colloidal silver in a nebulizer (to breathe in the vapor) can help, but we haven't tried that yet. Maybe sit in the bathroom with the shower running really hot to create a steamy room.
We also use cough drops, there's a brand called Sucret that works well for Brett, even though he hates the taste. And my husband absolutely swears by a super strong brand called Fisherman's Friend.
I have a spoonful of honey or add honey to tea, depending on my mood. (I also use it for sore throats.) I also like Traditional Medicinal (? I think that's the brand) teas--they have a couple designed for colds, coughs, throat coat, etc. and they're usually available in the grocery store.
Also, for colds/cold symptoms in general, I find a lot of hot sauce helps a lot for whatever reason. Also, a hot shower can be great. Oh! They also make effervescent tablets you can pop in your shower--they dissolve in the hot water and smell like eucalyptus and whatever, and they can help clear up a cough or whatever.
Not natural, but I've also taken to using Halls lollipops instead of cough drops. They're made for, like, toddlers, but I like them because the menthol is a little less intense than a traditional cough drop while remaining effective.
Update: the hot shower helped a ton with being able to breathe. Drinking honey was rough, it’s too thick and made me gag (I gag on pudding so I’m not surprised) but it helped the cough! I got some lemon and honey cough drops, and that seems to help. They’re not all natural, but oh well it’s all Walgreens had