Hi
PFIC rules are complex and probably need you to look at the exact details of the investment to be absolutely certain - and it may be the case that your US preparer has done that, so they're in a better position to be sure.
That said, if you have invested in a company whose business happens to be fund management - and you just own shares in the company, there are no underlying investments in the funds that they invest in - to my mind, it's not a PFIC, it's just shares held in a company (in the same way as if you held shares in any other UK based company).
For your second question - a UK (or other non-US) brokerage account in it's own right won't be a PFIC - it's about the investments held within it. So if you held a brokerage account that held shares directly in a few companies, but also invested in funds - the brokerage account itself wouldn't be considered a PFIC, and neither would the shareholdings. However, each investment in a fund would likely be a PFIC.