cough/cold in 15 mos old

Hello Dr Mom, my 15 mos old son can't seem to shake a cough and cold he's had for a couple of weeks. He has a runny nose and his cough wakes him a lot at night and during naps. I don't want to take him to the dr as I know he will recommend antibiotics. Any recommendations that I can do for him or something to give him?
Thanks, Samantha Tweet