You just got the best...
You just got input/feedback from some of the best (my current fav phrase) this board has to offer.
take your time, but really, really take it to heart.
Your presence can do as much harm for dad's case as good and all it can take, if mom is intent and/or vindictive enough, is one mistake on your part, for all of dad's hopes to crash.
The court does look favorably on a parent that has completed their reunification plan and the court looks favorably on a parent that has stepped up to the plate in a time of need.
the court doesn't look upon a third party interfering well at all.
the trick for someone in your shoes is to learn to care 100% and stay in the shadows in the same percentage.
It's like peeing yourself in black pants.
all you get is a nice warm feeling.
i had a snappy little end to that saying for steps, but geez, i forgot it! so i leave you with the nice warm feeling.
research 'disengagement for step parents'. well worth your time.