Concerned sister

So i have a concern for my sister. She 23 weeks and for the past 2 weeks shes been having light spotting brownish. And then 2 days ago it was red and a little heavier maybe .25 cup. She went to the hospital to get checked and her cervix is closed. Shes in no pain. And they just send her home. I was wondering if anyone has any ideas or similair stories. We get worried because she did have a miscarriage and eptopic pregnancy 4&5 years ago. Thanks.