Would it be easy for for my sister to get the kids back since I only have temporary custody?

My sister is currently in jail and will be for a few months. I got emergency custody of her 2 boys a few months ago when she went on a drug binge and tried to commit suicide 4 times in 24 hours. She has an older son that was lost to DHR 6 years ago and a 2 yr old daughter she signed her rights away for her when she was a little less than a year old. She does not know who these boys fathers are and has only had them about 9 months this time she had left them with an ex who was not there father for almost 2 years. She has a pretty extensive arrest record. She is now for the 12th time after being arrested saying she will straiten up and wants her kids back when she gets out. I was wondering if this will be possible for her? I was granted temporary custody but we have not yet been to court on this.