I'm trying to get caught up on the latest with this case because for a while, it seemed like it was going nowhere fast. Now it seems that LE has a theory in mind and maybe we will finally get some answers.
As for Sergio being gay or not, I can't see where that has ANYTHING to do with Isabel missing except that the parents being no longer together. Parents can be separated for a number of reasons, that being just one of them. The fact that he his allowed no contact but he has not been charged with anything leads me to think they want the father isolated for some reason to get one or both sides to talk.
What I also wonder is if Sergio was not in fact living at the house and maybe showed up early to take care of the kids while mom went to work. She may have not checked on the kids. Maybe SHE was not staying at the house. In either case, what I sense is some behind the scenes blaming going on between the parents because they were not in the house together the whole time that night. I find it hard to believe, whether they were 'together' or not, that if they were in the same house that night, they would not be putting on a more united front. I think one of them was not there overnight.
Secrets will come out soon enough about their domestic arrangement, the no contact order and any dealings like gambling that may have been happening on the side. The fact that the father was not arrested or charged says something. And yes, I still believe this is some kind of inside job.