…sights and sounds about him, all contributed to this state of feeling; but when he recollected that, being there as an assistant, he actually seemed—no matter what unhappy train of circumstances had brought him to that pass—to be the aider and abettor of a system which filled him with honest disgust and indignation, he loathed himself, and felt, for the moment, as though the mere consciousness of his present situation must, through all time to come, prevent his raising his head again.
There are no more uses of "abet" in the book.
Show samples from other sources
The man who could not be discourteous to a ground-squirrel had sat in the courthouse abetting the cause of grubby-minded little men.
Harper Lee -- Go Set a Watchman
Not telling her is tantamount to aiding and abetting the enemy.