Get him a used 335i and take out a good life insurance policy as well as a bodily injury policy so you can at least make some money when he does something stupid. Also make sure you have a good umbrella policy$1-$2 million should suffice.
2013 X1 35i M Sport - Mine
2012 135i M Sport - Wifey
2014 ZL1 - Mine
2014 Harley Davidson Street Glide Special - Mine
2014 Harley Davidson Breakout - Wifey