This sounds pretty dangerous - even if the executives of a company claim that it is confidential, why should the employees believe it? Therapists talk about their patients in a very general sense all the time, and even if they don't, an employer is going to want to have some idea of how the therapist's job is going. In a small company, it would be far too easy to put two and two together, and then react in a way that…
The company is in the UK so there are laws governing use of information. Hopefully the company chose a BACP registered therapist and so that therapist will be covered by their registration rules too.
There are laws governing the use of that information in the US as well - some of which exist federally, as well as some on the state level (which may be stronger than the federal ones).