Theres essential oils that they make for babys and toddlers. In the baby section at walmart. I can vouch for them. I still use them on my daughter, and the cough and cold one worked wonders.

Baby chest rub, humidifier, I second zarbees and prop them up to help drainage

Try the nose water thing where u squirt the water up one nostril and it comes out the other side pushing out all the boogers I forgot wat it’s called