The phrase "although he helped" is correct and usable in written English.
It can be used to introduce a contrast or exception in a sentence, typically indicating that despite the help provided, there is a different outcome or situation.
Example: "Although he helped with the project, the final result did not meet our expectations."
Alternatives: "even though he assisted" or "despite his help".
Although he helped the Yankees win the World Series in 2009, he has struggled since.
Although he helped restore the Rump Parliament in May 1659, he soon broke with it and dissolved it by force.
Although he helped obtain Parnell's release from prison for having attacked the Irish Land Act of 1881, Parnell came to mistrust him.
Although he helped to start and acted in an avant-garde theater troupe when he was 18, Mr. Fischer never trained formally as a theatrical artist or director.
Although he helped the Tigers win the American League pennant that year, he went to the plate just once in the World Series, recording an out.
Although he helped Penn State capture a Rose Bowl title, Collins has been to the playoffs only once in a National Football League career that began in 1995.
Not explicitly, although in 2008, he helped to bankrupt a company that helped to almost bankrupt the global economy.
TR's nephew, Franklin, would have to repeat this exercise in the 1930s and would be called "a traitor to his class" for reining in the type of corporate excesses that brought about the Great Depression, although, in effect, he helped save capitalism from the capitalists.
Although domiciled in London, he helped to mold the styles of two generations of American painters.
But he was not an investor in the most successful of all the companies he helped, Google, although he did receive some shares as compensation for his advisory role.
And Jordan then was not the Jordan he became, although he had helped lead North Carolina to the N.C.A.A. title in 1982.
