As an educated young woman I’d assume you’d know that “intervention” is usually “painful” for the “patient” but must be done nonetheless. (I know we’re talking about ruchnios but the principle still holds true.)
The fact that your likability with him registers higher on your radar than his tachlis, which was supposedly the premise for your posting here speaks volumes.
Many Rabbis won’t get involved unless the person makes the initial contact since they want to know there’s who to work with, so you’re VERY LUCKY you got a Rabbi to go on campus first. Grab the opportunity!
And finally, did this Rabbi recommend you get involved personally?