The thing is that it's easy to stop Java applets from executing. Even better most browser prevent this by default. Including chrome, which he was probably using as indicated by the screenshot.
Looks like this was entirely his own fault, though it still sucks. Wouldn't hope for a refund though t.b.h.
This is exactly why everyone on the internet keeps saying that you shouldn't automatically run Java applets or shouldn't have Java installed at all on your computer.
Java is just such a big target for hackers nowadays, that there will always be zero-days.
Looks like this was entirely his own fault, though it still sucks. Wouldn't hope for a refund though t.b.h.