My 1 year old son has a chesty cough & when he drinks his milk he vomits it all up. Please help!?

So sorry to hear what you are going through. You need to stop giving him milk because it only creates more mucus and will not help him at all with the cold symptoms. A nice warm bath to help the drainage, humidifier to keep it loose and pedialyte. You need to start replenishing his fluids, the lil ones dehydrate so much quicker than adults. But stop the milk for the time being, what I have suggested will at least help comfort him and maybe allow you both to get some sleep before you get in for your scheduled doctor's appt. I hope all goes well, you can expect this cold to last for at least two weeks, for some reason it is hard to shake this year.