Instead of correcting the child's spelling for him (when he won't pay attention to it anyway)....
Try this: Put a x or a check mark in the margin for each spelling error on that line.
Ask him to find and correct the spelling errors on line #1. Proceed line by line.
Teach him how to use resources (e.g., www.dictionary.com) to check on how to spell a word.
Turn it in to a game by awarding points for each word corrected.
This empowers the child to correct his own spelling and isn't overwhelming.