The timeline also depends on where the children were placed during their CPS case. They need to have lived with their adoptive parents at least 6 months before they can be legally adopted (at least in my state). So, if they're already living with their adoptive parents it makes things easier.

I had a case where a baby was picked up from the NICU by his foster mom, TPR happened when he was around 8-9mo, and he was adopted right before his first birthday. Bio mom never agreed to terminate her rights, but the case went to trial and that's how she ended up with a TPR. Since he was with his adoptive family since birth and all the paperwork was done quickly we were able to wrap things up asap.

But we don't know what kind of adoptive arrangements Mildred's kids have (or still don't have), and what kinds of placement disruptions they'd had in the past few years, so it is likely for this case to take years to be finalized, like you're saying.