paying3tuitions

D's good college girlfriend, two years older than herself, moved to NYC after graduation. Several months later, the girl began to describe to her Facebook friends (with very appropriate language, judgment etc.) how she had a met an attractive young man, naming his alma mater and unusual job. My D figured it out: she was reading about her own big brother! In that huge city! Not wanting to jinx the relationship, she stayed silent to both of them on it. Anyway, two years later and all those relationships are still flourishing.

I realize this is different than the OP's situation. It was Facebook, not google; and all the details written online were plenty modest. They were college graduates who knew not to be foolish online.

If something immodest were published by a girl about my S, I'd go Curmudgeon's approach and tip S off. In the final round, you need to be loyal to S and let him protect his reputation, especially if the girl might publish more in the next installments!
Just be sure to let S know you're not offended by anything you read (lie, if you must) so he can focus on his OWN opinion about what she wrote, not your embarrassment.

You can certainly tell him you discovered this by googling him. It's flattering, really, to google someone. I track my cousin's professional papers, etc. this way. Tell him you just do this to keep up with everyone in the family you admire, including him. And woops, you found something he needs to double-check. Just send the link and add NO thoughts about the link. Curm is even more subtle, so better yet.