[MO] Why aren't there repercussions for those who give their keys to drunk drivers?

This is mostly out of curiosity, but something I've encountered. My brother was arrested for aggravated DWI and driving on a revoked license (yeah, he's a felon, and he's now serving time).

Obviously he's responsible for his own actions, but I found it strange that the woman who provided him with the keys (and was in the passenger seat): (1.) Knew he was drunk (2.) Knew he did not have a license; but she didn't face charges.

If a bartender can be held responsible for a drunk driver, why wouldn't a person who knowingly and intentionally gave their keys to a drunk person?

(Edit: To the person who snottily replied to comments, I saw it before it was deleted. No, I'm not asking why a victim of DV wasn't punished. I'm asking why the perpetrator of DV, who gave her keys to her drunk victim, faced no repercussions for the fact that a drunk person was driving her car, with her in the passenger seat. It seems like knowingly allowing a drunk person to operate your vehicle should come with at least a ticket.)