I'm going by what you have told me. It is possible to get hypothermia is the wind was blowing and he was wet.
It is also very possible that he is coming down with the flu (the flu is a virus).
You have said he feels drunk, his eyes are blurry, and now they feel hot. Feeling drunk with blurry eyes could be from hypothermia, or from the immune response - in other words, his body's reaction to the flu. Eyes feeling 'hot' sounds more like perhaps his temperature is starting to rise but it is hard to tell.
The main thing is not to panic. When he feels cold, keep blankets on. If he starts to feel hot then take the blankets off. Drinking plenty of fluids will help his kidney function without stress and help his immune system fight off the infection. Non sugary fruit juices or real fruit may be helpful, if this is virus related (won't hurt if not).
As I stated earlier, he can take Ibuprofen or tylenol to settle the chills down. Some chilling is okay, that is how the body mobilizes it's defense system. It is a normal response and does not have to be stopped, but if he would feel better he could take tylenol or ibuprofen. Rest is important and he will get better quicker if he rests, drinks plenty of fluids, and is not stressed out.
If he does end up having flu symptoms, you can see a doctor and sometimes tamiflu can be given, but this is not always prescribed, as it is sometimes better to let the immune system do its job by itself.