Sorry to hear this Steve.
A lot depends on whether the police are pursuing any offence against this woman or not. If they are, then any insurance claim is likely to go on hold pending the result of the police case. A conviction wont do your son's case any harm. Similarly any civil proceedings you might want to take will be after the result of any police case is known.
It's early days yet to know what the long term implications are for your lad in lasting ill-effects, loss of earnings etc. - all factors which will affect any claim he might want to subsequently make.
Lots of solicitors offer 20 mins to half an hour of advice for a very modest fee, and it may be adviseable to take that route ASAP for guidance, but I'd be wary of getting a solicitor on the payroll too early if were you.
