Posting sickness and everything you can about their conditoin may help. If what they have is not bacterial, such as how 99% of the time respiratory issues are viral, the only thing antibiotics will do is fight off secondary infections and kill of all the good bacteria required for proper digestion.
Bacteria are your friends in 99% of the cases, with the majority of the time the good bacteria out competing the "bad" so the "bad" can never make you sick.