So, with this they can save cocos mother now, no?

They would probably have to reverse time on the sigil and not the mom. I’m thinking if they reverse time on the mom she might forget. I could be wrong, maybe the author forgot that he made it where coco has to find the sigil to reverse the magic

They still don't know the sigil for her mom, and they used a curtain leech shaped spell. Unsure if there's a spell that would be in her shape of Coco's Mom or not. They're a lot closer than before though