Have you tried using a humidifier in his room at night? It just helps loosen any mucus and soothes their throat a bit. I find it helps with my little ones. Not ever had any success with cough medicines
Opened bottle of peppermint or eucalyptus oil at night helps us
Warmed up apple and blackcurrant juice, I tend to put a little bit of honey in it too! It’s yummy and it works miracles for my little girl x