Good question. An accidental overdose perhaps? Hence the sleeping?
One other thing struck me as odd. In this article it says
"She told me she was staying at her father's house," Terry explained, but that wasn't the case. "I went to pick them up Sunday…they told me she was back over [at Julie King's house],
where she promised me they weren't going to be."
http://www.toledonewsnow.com/story/22481101/day-3-and-still-no-sign-of-missing-toddler
bbm - Mom promised him they were not going to be at JK's house. Why? Because something happened to the girls there in the past? Was this part of why he wanted custody for both the girls? And that's why mom was crying and saying she will never see her again if she would give her to her father?
What happened in the past in that house, either with the bf or the bf's mother?
....