Delphi, which is based on object pascal, is in 9th position on TIOBE index. I’ve programmed in Delphi for 8 years. Back then it was one of the most advanced language you could code on in Windows, considering that .NET languages came years later (with a great contribution of Delphi gurus).
That being said, a school should teach programming and should use a language (or more) that can support its teachings. It would be hard to teach OOP if the language doesn’t support it.