Child custody should I take the chance? what would you do?

Ok long story short. me stepmom have 3 step kids thier mom walked away from them 3 years ago for a drug dealer and got pregnet now she wants to be back in their life but after she has mental tortured them by phone over the last year. I have it on tape because at the time I recorded it I didn't know that she had to know it was being recorded anyway going to court soon and with the tapes I can prove drug abuse, phy. abuse, mantal abuse, abandonment, and medical neglaect. but if I use it then I could be fined or even spend time in jail. what i need to know is how many mothers fathers or steparents or aunts uncles or loved ones would put themselfs in my shoes and take the chance. I really love the kids and am only worried about there safty and happyness. I would love it if she was a good parent still but since she married this guy she has only gotten worse. she had custody of kids for a few years after the devoriced and provided a save home then one day just left and didn't come back or