Was it an English teacher in high school? An editor for the college paper? An English as a Second Language instructor? Who helped the writer for Yahoo! Sports learn grammar? And how can we stop that person?
This is what is sometimes called hypercorrection: The use of a word that sounds more intelligent, sophisticated, or erudite to the writer, but is actually incorrect. The correct word is him; it is the direct object of the verb helped and therefore the objective case is called for.