The article's exact words are: > Google found her claim credible, they said. The company did not fire Mr. Singhal, but accepted his resignation and negotiated

The article's exact words are: > Google found her claim credible, they said. The company did not fire Mr. Singhal, but accepted his resignation and negotiated an exit package that paid him millions and prevented him from working for a competitor, said the people. Given the specific wording("found her claim credible"), it seems quite possible they did not have enough evidence to bring to court in case of a wrongful firing suit.