Yes, essentially I think he gave a championship to Fangio (1955?), and didn't Tony Brook give his car up for Mike Hawthorn in 1958 as well to do the same, or are we both thinking of that incident?
ah, just looked it up, Moss defended Hawthorn to the Stewards so he wouldn't get DSQ, which gave the title to Hawthorn at his cost, Collins gave his car, despite not being asked, and the title, to Fangio after Musso had been asked and refused. Collins later explained the reason for his action. "All I could think of was that if I won the race and the championship I would be an instant celebrity. I would have a position to live up to. People would make demands of me. Driving would not be fun any more, so I handed the car to Fangio. I am only 25 years old and have plenty of time to win the championship on my own." Within two years he had joined the depressingly long list of Ferrari drivers killed racing.