Without seeing the CCTV coverage and/or being privy to the discussions between the police and the CPS, a lot of guesswork is needed from anyone posting here.
However it's likely that the CPS would first want to see if they could get a prosecution for any type of assault offence to stick. It's unlikely that they'd find that there's sufficient evidence to prove 'attempted murder' and their own website makes it clear that there's no such offence as 'attempted ABH', so they might consider the possibility of a charge of 'attempted GBH'. However I suspect that the evidence wouldn't meet the threshold for such a charge.
They might well then consider a charge under Section 4, Section 4A or Section 5 of the Public Order Act 1986 (
https://www.legislation.gov.uk/ukpga/1986/64 ), with the use of either Section 4 or Section 4A probably being more likely than Section 5. Such an offence can lead to up to 6 months imprisonment but I doubt that such a penalty would be imposed for the offence you've told us about.
In practice the CPS might prefer to concentrate on the one charge that they would find easiest to secure a conviction for. i.e. one of 'dangerous driving'. A conviction for such an offence can also lead to imprisonment for up to 6 months but, once again, I think that it's unlikely to happen in the circumstances you've described to us.
The CPS website states "If the driving that caused the danger was taken as a deliberate decision, this would be an aggravating feature of the offence". Given that ANY conviction for dangerous driving AUTOMATICALLY results in a MINIMUM driving ban of 12 months (unless there are extremely exceptional circumstances), a longer ban (of perhaps 18 months?) might be imposed by the court upon your neighbour's son.
As I wrote at the start, a lot of guesswork is involved here but I further note the following from the CPS website (which makes public the advice given to its own staff):
"When a vehicle is deliberately used as a weapon to cause injury, prosecutors should normally prosecute for the offence of dangerous driving, or a specific assault under other provisions in the OAPA [Offences Against the Person Act] 1861, subject to there being sufficient evidence to provide a realistic prospect of conviction, for one of those offences".
So my best guess is that your neighbour's son will end up with a driving ban, possibly of around 18 months, for dangerous driving. He'll also be required to take an extended re-test before he can regain his licence. He'll probably also be fined, ordered to pay a victim surcharge and required to pay costs.
https://www.cps.gov.uk/legal-guidance/road-traffic-charging