Step children

My step Daughters mother has her in such a bad habit that she has to have someone in the room to go to sleep and if she wakes up in the middle of the night she will start to screams she's 5!!! It drives me crazy and I have a hard time not comparing her to my nieces which are 5 and 1 both who will go to sleep on their own no crying no nothing I'm scared she is going bring this bad habit to my children and I'm not having that... And my husband gives in everytime which is the worse part I tell him to let her cry but NO!!