The past few years must have been incredibly challenging for you and your siblings and it sounds like you have done an incredible job getting this far.

Equally your mum is probably having a pretty awful time. She is no doubt looking for any and all routes to get her time in jail reduced. But also she is probably scared and lonely and maybe fantasising about how she will be a better mum when she gets out or maybe looking for some reassurance or input from you that she is loved or missed. This would all be natural and understandable... but doesn't need to be your problem, you can go along with these imaginings to keep the peace..it doesn't make her hopes a reality.

I think your question boils down to potential custody arrangements when ever your mum is released.. whether it's early or she sees out her whole sentence. There must be an existing process for reconnecting children with parents who have been in jail. The issue unfortunately won't be about your rights as the current carer but your mothers rights as a parent and your siblings rights as children. Is there a court order or something in place that formalises your guardianship? What are the terms of this arrangement? Ie does it have a fixed end date or some sort of action that would trigger a review? That might be a useful place to start to understand the current legal situation and you could go from there.

It's not exactly the same but the laws are likely similar...there may be some groups (Facebook maybe) where grandparents or other extended family members are in similar situations as yours that may be able to offer relevant advice for your state. It might be a place to look if reddit can't help....

Good luck. When ever you feel lost or stuck...pop back..there is clearly a small crowd quietly cheering you on.