Discipline with a mixed family

[Angel_sunshine2]

My fiancee and I have been living together 2 years now and I have a 16 year old daughter and he has a 12 year old daughter and 1 16 year old son.  He has joint custody so he gets them every other weekend.  We have a rule that as long as they get up by 11 a.m. they can stay up a little while after we've gone to bed but not like extremely late (12-1). Well while my daughter and his son go to bed when they are supposed to his daughter will stay up all night and want to sleep all day until someone literally wakes her up.  I've taken her phone and laptop and he supports my decision for that punishment but does not help me reinforce going to bed and only tells her not to stay up too late.  We've gotten in arguments in the past about this because I've let him know that if he doesn't do like me and take her phone it shows her I'm the bad one because dad doesn't care.  How can I get him to compromise with me and what else can I do about the situation with her?  I don't want to nag about it I just want him to understand that he needs to do punishment as well but it always ends up in an argument and I give up letting her do as she pleases and let her sleep all day then he gets mad at me for saying something to him about it when I'm home and should have woke her up.  I'm to the point that I don't care anymore because I don't have his FULL support.

[Stepx2]

Not sure why a 12 year old should be allowed to stay up so late? Not healthy. Make sure she goes to her room no later thawi 10. Rem electronics. She will either read or fall asleep. Also if your children were involved in activities they would not be sleeping so late.