14 month baby cough. Is fully active.

My son weight 11.3kgs, and 14months old is having cough i.e. he is actually coughing from 2 days. He got this infection from me. I'm taking the necessary medicine and I'm giving him Prospan 2 ml twice a day. But no use. He coughs 5-6 times a day and even at night in his sleep he coughs. His appetite for solid food has also reduce significantly. He drinks lot of milk and dal soup. But very less solid food . He gets nauseated if we feed him solid food and tries to vomit but does not vomit. Pls suggest all do's and don'ts and if I need to give any more medicine or any home remedy. He also sneezes occasionally. And the temperature outside in my area is 21° he doesn't have fever and is fully active.