calling to investigate my mum

N🌻
Today my mum hit my two year old brother really hard. So I told my older sister who doesn't live at home and she's put a complaint into what you would call "child protective services" but my countries version. She did that because I was scared that if I did it I'd be kicked out of home and have nowhere to go. Do you think I did the right thing? 
 Here's his arm roughly two minutes after it happened and I stood up for him the best I could. I yelled that she shouldn't hit her children and if she couldn't look after them to not have them. I then took my brother into my room for an hour and let him watch a movie while I explained to my sister what had happened