Thanks for the advice.
Unfortunately, some time has passed since this actually happened and the credit card bill has had to be paid. The c.c. company seem to be saying that he agreed to these people taking money by c.c. so they (the c.c. company) can do nothing about it. That seems odd to me though, especially as he hasn't actually got any "product" for his money.
My BIL isn't a Net user but I've been trying to find out about this "company". Sadly it appears they've stung hundreds of people, including many in the UK, using the same old guff. They seem to use many guises, one sunny travel company after another, all peddling the same old con. It isn't clear whether many, if any people get their money back.