One night I was coming back at home, it was pretty late and temperature was around 0 degrees. Time to park the car and while the lights were still turned on I notice a hedgehog just in front of me, in the facing garden. I get then a little bit closer but not too much and notice that he's breathing quite heavily as I see the spines coming up and down pretty quickly. Ok, I think that I've scared him and I turn off the lights. But he continues to stay there. I realize that he's probably smelling me hence I leave the place to allow him to get somewhere else.
2 days ago in the morning (around 10am) I was taking away the snow from the car and I see the hedgehog (not sure if it was the same) litterally walking in front of the main entrance door of the building going from one side to the other and then disappearing again into the garden.
Now:
1) Aren't the hedgehogs supposed to sleep during the entire winter?
2) Isn't too cold for an hedgehog to stay outside with 0 or -2 degrees?
I've talked to a couple of friends and some of them said that probably somebody destroyed his "home" and it has been waken up from hibernation. Or probably he's starving and he came out in search of food?
Here and there I've also read that if a hedgehog wakes up from hibernation it means that he's sick and have very few possibilities of surviving
To remedy to this I've taken in consideration the possibility of bringing him into my flat but I guess it would sh** everywhere and probably would get into depression due to the change of environment. The best solution would probably be to build an "home" for him but just figure how badly my swiss neighbours would look at me while I build a tunnel in some corner of the garden placing leaves inside

... adding the fact that I would be unable to give them an explanation as my german stays to zero.
Is there a way to save an helvetic hedgehog?