The law regards permitting someone to drive their car without insurance in exactly the same way as it does actually driving it without insurance. So, yes, your wife can be prosecuted. The minimum number of points that a court can place on someone's licence is 6. (The range is 6 to 8). As it seems likely that that would bring the total to 12 points, a court would be obliged to consider a ban (and to impose one unless there are exceptional circumstances).
You state that the 6 points on your wife's licence are 'from about 3 years ago'. If they're more than 3 years old, she'll have expired and (apart from having to pay a higher insurance premium) she'll have nothing to worry about. If the points were just about to expire, the court might take a lenient view and either not impose a ban or only impose a short one. (Even a short ban, though, is likely to result in at least a doubling of your wife's insurance premium. It may well be quadrupled).
Chris