The state is gonna push for TPR

One of my foster kids father has been trying to get custody back for the last year and a half. He was actually taken away from his mom because of severe child abuse charges that she got arrested and charged for. She is serving 7 years for the charges. His dad was on drugs which is why he couldn't get custody. His dad has had moments he's sober and doing well and following his plan and then he relapses. I thought everything was going well. His dad has been at visitation and just recently celebrated his 14th birthday and his dad put together the party and it all went really well. But Thursday the social worker told me the state is gonna push for TPR. I asked why. I thought everything was going well but she said dad failed his drug test. It's been a year and a half almost 2 years. Pushing for it doesn't mean the dad still can't turn things around and get custody back. Just that they are starting that process. I'm just trying to offer all the support I can because TPR is always so hard. Especially with situations like these where I know the parent does love their child. I'm not sure what I'm looking for here besides people sending out positive energy.