Everyone is sick😞

I need advice about what to do for my 3 year old who has had a cold for 2 weeks. My 8 year old, 6 month old, 3 year old and myself are all sick. I can’t give anything to the baby obviously and my oldest has been using Tylenol cough and cold but what, if anything, can I give to my 3 year old? He is literally coughing nonstop😭People keep telling me to give him half of the dose of Tylenol or use all natural medicines. I’ve tried the all natural stuff in the past and it’s useless. Advise is needed here. Thanks!