G.B.
I use Children's Liquid Sudafed to keep the drainage thinner. It goes down at night instead of drying in the throat. I'd suggest if they have any drainage giving them 1/4 dose and up to 1/2 dose. They don't need a full dose.
I get mine from a local family owned pharmacy that can order from their own suppliers instead of chain pharmacies that only order what their warehouse buys. My Sudafed is by Rugby.