Here's why he was called Il Pazzo. But he certainly has the top notes.
Il Pazzo means the crazy man.
Franco Bonisolli and Franco Corelli died on the same day rather like the way John Adams and Thomas Jefferson died on the same day. (Amendment - apparently I'm wrong about this but I don't care)
Bonisolli was a competitor to Pavarotti in a sense. SF Opera put on Gioconda for Pavarotti. When it was revived Bonisolli replaced him. Pavarotti was smoother but Bonisolli was more fun. He struted around and he posed. And he sang some great high notes - bigger and better than Pavarotti's.
Bonisolli's voice wasn't too big when he first went international. He sang Almaviva in Barber at first. He always had the top but only later did it grow and blossom. He became a high note tenor like Filipeschi.
You can hear all the "gear changing" he needs to do in the middle voice, but all is forgiven when the line goes above the staff. He goes to squillo-land.