Sister-in-law created Facebook page for her underaged child. Should I do something?

[Mindy]

I just got married a few months ago and am not yet super close to my husband's family, but we are Facebook friends. Last night, my husband got a friend request from his 10-year-old nephew. His mom included a note that her child would be allowed only 10 friends who are friends and family. She posted on her status report this morning that to all the people wanting to friend him, she was limiting him for his protection, but that as a new homeschooled child, he was lonely and needed more interaction, and that this could help fill that void.
I work with kids and am concerned. Facebook allows only users aged 13 and up, so she falsified his date of birth to get him on there. The advertisements target people older, not to mention the fact that, even if he only has a few friends on there, not everyone has their security set up to protect young children. And, though unlikely, predators will always find a way to try to reach kids. Anyone can still message him through Facebook.
My husband tried to change all of his security settings, but he can't control what others might post to his page (and shouldn't have to), and if my husband makes a comment on another friend's page who doesn't have high security settings, the entire conversation string might be seen on the kid's home page. I say this because my husband's oldest daughter is an artist who posted a drawing that was really beyond R-rated one time--he made a comment on it that reminded her that her grandmother could see that picture. Had he and his nephew been friends at that time, his nephew might have seen the comments AND the picture on his homepage. And his parents would have been furious.
Anyway, it isn't fair that my husband will have to think about every post he makes and whether it is appropriate for a young child to see.
These parents are the same ones who tried to make sure the kid didn't see a nude (tastefully done) painting in a restaurant we went to several weeks ago, so they're normally pretty protective of him, and they are very religious.
I was half tempted to report this (if you report underaged users to FB, they delete the profile), but I kind of made a stink to my husband to talk with them about it, so if his page is deleted, I think people will know it was me. I don't want to start my relationship with his family being called the "busybody," judgmental, or "the police"...
Any ideas? Or do I just leave it alone? My husband doesn't want any bad feelings, but it really irks me when parents do something that is inappropriate for their child or that makes others have to be responsible for their children.
Thanks!
Thanks so much for everyone who took the time to answer. I found Steve's, Tiffy's and Maternal and Family Health's answers particularly helpful. I ended up just telling my husband my concerns and giving him some other ideas for sites (thanks, Steve!) that the kid might like to visit and left it up to him. I noticed yesterday that he had friended his nephew, so so be it. Now it's just his parents' responsibility, even if I don't agree.
Thanks, all!