This Pregnant girl is drinking alcohol and also riding roller coasters.?

My brothers girlfriend is pregnant and is drinking alcohol and then today she went to Busch Gardens an rode all the roller coasters. She shouldn't be drinking bc she's only 18, an the thing is my brother is 28, an he knows that his child can come out messed up. It upsets me bc I can't do anthing about it or can I ?. What to do?