According to the Boston Globe, he can get a year for resisting arrest. I don't know how much the other infractions will affect him.
Crumple zones are amazing things in cars, because they allow people in accidents to come to a stop over a longer distance, reducing the force on their bodies. I don't know how much distance this ends up being in a Bentley, but I do know some basic mechanics in physics. 143 mph is about 210 feet per second, so assuming a stopping distance of 4 feet, we're looking at an acceleration on the human body equal to:
a = v^2/(2x) = (210 ft/s)^2/(2*4 ft) = 5512.5 ft/s^2 * (1 g / (32 ft/s^2)) ~= 172 g-force.
Referring to a website (
http://hypertextbook.com/facts/2004/YuriyRafailov.shtml), this impact is definitely fatal. Even if the Bentley were to strike a single car at rest with the same mass in a perfectly inelastic collision, while the g-force *should* drop to 43 g (assuming speed is just relative here), this quantity is actually an average -- given that the acceleration won't be cleanly constant, the top deceleration will be a bit larger, and there's a good chance the kid still dies... and it'll probably be fatal for everyone else anyway if the crash isn't a clean one-car resting collision (like if the crash is at an angle and causes the car to spin, applying forces in directions that the human body handles worse than a head-on collision; the driver and passengers aren't facing forward; there's a pile-up or multiple hits; if the target vehicle is larger than the Bentley; or if I'm significantly overestimating the crumple zone). This is unquestionably fair game for a maximum in a reckless driving case, which in Missouri is worth 6 months if there is no accident:
http://www.leadfootspeedingticket.com/2014/05/careless-and-imprudent-reckless-driving/ (and a class 2 misdemeanor).
I don't know whether the endangerment of a minor will involve charges that will be pressed, but if it is the case, it'd be a class C felony:
http://www.moga.mo.gov/mostatutes/stathtml/56800000452.html (with a penalty of up to 7 years, but courts get discretion, as this case may not necessarily justify the maximum felony C sentence:
http://www.mosac.mo.gov/page.jsp?id=45441 )
18 months definitely seem to be on the table, but plea deals, probation, and the involvement of a child (felony) are wildcards in this matter. And I frankly have a hard time putting a number on this sort of thing in terms of what is "right." That said, 143 mph on actual roads is just mind-boggling -- "just" going over double the legal speed may not be a big deal, but legal speed limits are a lot faster than we give them credit for, and a lot of things in math translate to an over quadruple effect (energy, stopping distance) or worse ("jerk" would be over eight times as severe). Going that fast on public roads defies any sort of connection to reality, and he can't be separated from society to start (what needs to be) rehabilitation soon enough, nor can be allowed to drive a car for a long time (years).