@jim
Come to think of it, it would have been within a skeptic's discussion forum that the description I am recalling was brought up, so you're not the first person I've (not)met to view him with dubiety (if there is such a word?)
The gist was that, if you wanted to know whether your garden party or wedding reception was likely to be spoiled by the weather, you could find out for a small fee.
Of course, since there is a preponderance of these things in June/July/August, it's a shooting-fish-in-a-barrel task to recommend "the third week in June" or the "second week in July" as being good weeks to hold the event, take the money and not suffer much risk of any comebacks.
If the customer enquires about the weather on a specific day, however, that could be perceived as a greater challenge than picking "good week/bad week" except if you see it as a binary situation "sunny=good/rain=bad" making it as easy as a coin toss to get right.
Establishing whether his forecasts were consistently better than chance would require months' worth of forecasts and MetOffice data to compare it with. Nobody has the money, let alone the time.
Also, with solar activity mooted to be the foundation of his forecasting techniques, you would think it would be the gross (global-scale) climate mechanisms being impacted, leaving him only able to say, in general terms fair/foul, windy/calm, warm/cold and only at the scale of countries/regions, as opposed to the Met Office forecasts which can indicate rain showers in one town and all-day sunshine only 50 miles away.