My husband sleeps with his 12 yr old daughter

My 12 year old daughter has always slept with her parents. Even when they divorced, she continued to sleep with her dad ( not sure about her mom). We got married about 5 months ago and my 12 yr old stepdaughter wanted her dad to sleep with her (in her twin size bed). My husband is completely under his daughter's control and does whatever she says. The problem stopped for a few months, but now it has resurfaced on a regular basis. We moved into a new house when we got married. We all got new rooms ( including my 11 yr old son and 6 yr old daughter). We let my step daughter pick everything out for her room. Every night, she eats and drinks as much sugar as she wants and goes to bed whenever she wants. She keeps the tv on full blast and all lights on....but complains she can't sleep. He refuses to show her tough love. I' ve even tried Explaining to him that girls her age are developing and it isnt good to sleep w/her. I suggested buying her a book, so she can read when she wakes up and can't go back to sleep. But, personally, I thi k she is just using it as an excuse to control. Any thoughts would be helpful.....