He was at Oxford. He was at Magdelen. In fact, CS Lewis was his main tutor and advisor, and he loved Lewis all his days. Lewis loved him as well, despite his sharp disapproval. Unexpected, yes? Tynan died at 53 because of a lung disease, and went back to read a great deal of Lewis in his last decade. He had nothing but praise for him. In Alan Jacob's biography of Lewis, The Narnian, the last few pages are taken up with Tynan in his last years, possibly softening after it all to the call of Christ. His daughter Roxana read a passage from Lewis's "The Weight of Glory" at Tynan's funeral, identifying it as a favorite of her father's.
So we don't know what Kenneth Tynan thought in the end. But here's an interview from The Guardian, much more sympathetic to Tynan's POV than Lewis's, but Tynan holds firm. Notice how quickly the interviewer wants to get off the topic. There is something painful and poignant about it. In the last year of his life he wrote to his wife a prayer he had translated from the French and claimed as his own.
At the hour of my death, may You be the refuge of my astonished soul, and receive it into Your merciful breast.