Boyfriends 13 year old daughter

I have been with my boyfriend for almost 2 years. We recently moved in together in august after buying a home while expecting our daughter. This is not his first child, he has a 13 year old daughter that visits us every other weekend but spends the majority of time with her mother. About 6-8 months ago after Covid, remote schooling, no sports activities and a move with her mother his 13 year old daughter began having behavioural issues. I am currently 8 weeks PDD with our daughter, when we announced my pregnancy she took it hard as it was after her behavioural issues began. We explained to her that we understand if she has any negative or positive feelings about having a meeting sister and that we are here anytime she wants to talk. Her father tries really hard to spend individual time with her, including trips out of state. She will get in trouble at her mothers house and call her father to come pick her up - we are 2.5 hours away. He finally said no more, she needs to face the consequences of her actions at her mothers and stop bouncing from house to house only

When she is in trouble. Her mother agreed after a conversation even though she would want her father to come pick her up when things would get heated between the two of them for her defiance. The behaviour typically ranges from sneaking out, talking to boys online at 3 am, stealing from her mother or us (money, smokes from her mom or dad, packages from neighbors etc).

We were suppose to have her for a week beginning Christmas eve, her father picked her up and had a conversation with her regarding Christmas and behaviours. It was explained to her both by her father before opening gifts, then after by me that we are a dual income household now and can afford to do more for Christmas but this won’t occur again should her behaviour continue. She stated she understood. She received a ton of gifts and her father already didn’t want to do so much but I pushed for it.

I got her father a couple joints in his stocking for Christmas, he smokes (not ever around her) and we typically lock everything up in our gun safes. After he opened it, trying to do it while she wasn’t looking, he quickly put them in a drawer in our kitchen until he could get them downstairs in the safe. Long story short one of the two tubes has come up missing. We looked everywhere for it to be sure we weren’t accusing her but my boyfriend was certain as to where it was placed.

He called her out, told her she had 10 mins to place it in his hand before the gifts where being taken and he searched her room. Let me be clear this is not the first time we have smelled smoke in my home (her room) and we do not smoke in the home. Or she has been caught vaping at school. Of course the joint was found next to the garbage can close to the drawer it was in but I had checked there 3 times before she was confronted.

Her punishment has been to stay in her room with no electronics, she can come out to eat but then needs to return and he took her Christmas gifts. He has since again told her that this isn’t how he wanted Christmas to go and whenever she is ready to take accountability they can have a conversation but until then consequences remain. She asked to call her mother whom we have always had a good co-parenting relationship with. After she spoke to her mom, her mother asked to talk to her dad and reprocess to blame it all on us. We shouldn’t have had it in the drawer and have no hard evidence she took it.

Her mother now wants to come get her early to take her home but needs to wait for weather to clear.

We feel like her mom is co-signing her behavior and making it difficult for us to hold true to consequences for her actions i our own home

It was only me, my boyfriend her and our 8 week old.