Don't know what to do about DUI

Montreal, Quebec
My step son has had a drinking problem for several years. He has only been living with us for the last 7 or 8 months. Each evening, he drinks about 10 beers and goes to bed at 4 or so in the morning.
I have been after my wife for some time to ban all drinking in our home, and finally he left about 6 weeks ago and went back to his dads.
On new years eve, he got drunk here, and went out around 2 in the morning. The next morning his car was smashed up and he said that someone hit him and took off. The kid (19) is really messed up. He dropped out of high school about 4 years ago and cant hold down a job for more than a few weeks.
Anyways, last week he was very drunk and around 2 in the morning had a car accident at about 120km/hr. The car turned over several times and he was quite hurt and had to be immobilized by the paramedics. He was with another person in the car and he says the other guy was driving his car. The other guy says he wasn't. The other guy does not have a license and he was drunk too.
They were taken to the hospital, and the cops said they were going to charge him with dui.
Anyways, they never came back to the hospital, it's been a week, and t5he kid has not tried to contact the police.
Why aren't the police coming to get him,? He refused a breath test but later agreed to a blood test (he had been smoking grass as well).
Should he turn himself in? Or should he wait? What about his car?

Personally, I hope they charge him (so does his mom) since there is nothing anyone can do to get him to sober up. He needs a real wakeup call.