I think you’re too attached to the situation, and that’s impeding your curses.
I also think you feel this has to be your fight. It doesn’t have to be your fight, man. You do not have to be that girl’s last line of defense. Others can do that better than you because they’re closer to her than you are.
Cursing around children isn’t the way. Curse energy is heavy and brings a down to proceedings. The last thing you want to do is have heavy curse vibes around a baby.
There’s a strong possibility that either the mother’s aura is protecting the guy, or the child’s aura is protecting herself and guy is hiding behind one or the other to deflect bad vibes from himself, aka he’s using either the mother or the baby (or possibly both) to protect his selfish agenda.
Anything you throw at him would have to weaken them first, meaning either you’ll get the rebound, or you’ll weaken the mother or daughter’s aura in order to get an in. In which case the baby will likely get hit twice, first by you, then by the stepdad who is an opportunist and a parasite.
Instead of cursing, bring truth to the fore. Children require room and circulation, as well as total transparency, because kids like to move around a lot and need the space to grow their imaginations and their sense of personal boundaries. They need lots of visitors as well. Cramped spaces hinder their development, and lack of constant input slows their creativity. Also, separation from communities takes away from their sense of personal safety and confidence.
Use that knowledge to your advantage. Send beneficience to the girl to strengthen her aura and to attract community bonds with neighbours, friends’ parents, teachers, after-school instructors, anyone she sees regularly. Increase the circulation of traffic to her home by having her other friends from school do sleepovers at her home, calling her frequently, or drop in unannounced to say hi. Let her be constantly surrounded by support and love coming from all quarters. Make her so favored that others in her area check up on her at random just to be around her. You especially want pets such as dogs over - for some reason, dogs know who’s who, they can sniff out a wierdo in a second. Make it so she has many places to go for love and support, and many people to turn to who are looking out for her best interests, just because they admire her and want her to do well in life.
Perhaps put a spell on the girl using deerstongue, so that she tells everyone who will listen what’s going on behind closed doors. That way, the people that come to her are aware of what’s happening, and can verify it with the aunt so they know the daughter is not lying.
With that much love comes protection in the form of vigilance - that many eyes on her will surely see anything around her that’s not on the level. The increased insight of her revealing what others may not see will double their observation when they’re around, and eventually someone will step up and begin asking hard questions.
At that point it’s only a matter of time before stepdad tries a move, for it to backfire under the increased surveillance.
Think outside the box. There are many ways to solve a problem. Keep working at it until you find the ideal way forward for you.
And realize it doesn’t have to be your fight alone. Magicians are so quick to take on the weight of the world. You can recruit allies. Teamwork makes the dream work