How to I get my brother to care for his childrens teeth better?

I have a twin brother who has three daughters 4, almost 3, and 1. Now that I have started my dental hygiene program, I am learning how important it is to care for your children's teeth (it helps that while I am working in clinic, I can hear the children screaming from the dentist drilling). Anyway, I don't believe my brother is doing an adequate job managing his daughters oral hygiene. His older daughters refuse to drink tap water so he gives them bottled water (w/o fluoride) and my mom, who babysits for them 4 days a week, said that he doesn't brush their teeth often. How can I tell him that he should do a better job? Or is this none of my business?

He wouldn't talk to me for 6 months when I tolded him his gf was cheating on him....3 kids later his wife left him for another man.

By the way, I am a mother of a 2 and 4 year.

Sounds like HE's way too stubborn to listen to your advice, despite the fact that you've been right before..I would suggest starting with the kids, and teaching them good hygiene (make it into a game if you have to!), and talk to your mom about helping you teach them about brushing their teeth, and flossing (while she's there with them). At least they can develop healthy habits, regardless of whether or not your brother completely enforces it.

Maybe you could bring some toothbrushes and toothpaste home from the clinic and make it fun for his kids in a nice non interferring kind of way, and involve your kids with his kids in educating them all. Good luck.

Okay this is how i teach parents to brush their kids teeth ( im a middle schooler but it always works)
i show them pics of kids teeth who dont brush their teeth and say "do you want your kids to end up like this" and of course they say "no" and usually they get the point and take better care

i dont think that the cheating of the gf , that left him after three babies has much to do with the oral hygiene of the children.

its ok to drink water w/o fluoride.

now the problem is brought back to the right proportions.

It is not ok not to brush teeth daily.
How does your mother know that the kids are not brushing daily ?
If she is there why doesnt she brush the teeth of the kids ?
If she isnt there how does she know ?

I think it's great for you to have had your eyes opened regarding oral care! But don't think for a second that it's your job to supervise his parenting skills in any way, shape or form!

Do you not have enough on your plate with 2 kids of your own plus going to school???

No - it's NOT your business.

Here a a couple of suggestions. Buy the girls Pretty new toothbrushes for use at your Moms and also a set to take home (they love the character tooth brushes at that age)

You could get them different ones every 6 months or so. This might encourage them.

Maybe a good children's book on tooth brushing.