Ok, I'll jump in on this one. I know that I am not the most popular poster around here, but I think this approach makes sense. personally, this is close to what I think may have happened. as I mentioned previously, Gail really had a lot of loss in her life over the past few years. First her dad, then her brother. (Again, I wonder the reason's for their deaths...long battles with cancer or other serious illness can take a huge tole on family). If AD is being honest, there was another brother she didn't speak to-wonder why? Gail and family moved, she may have lost touch with friends, or missed where they used to live. She lost her job, My opinion is that her job was very important to her. Then she finds out that Matt is having an affair. Those are the things we KNOW about. There could have been other losses and heartbreaks that have not come up.
I think anyone facing that much hurt would be depressed somewhat. then, if she really started to think she was being followed, etc, (I can certainly understand that with all that was going on in the relationship.) Gail being as intelligent as she is, and with her medical knowledge, could have realized she was sliding down a slippery slope. Don't string me up for this, just reaching out for possible senarios, but maybe she had had enough, and was with it enough to think to herself-I need to step back, take a break, get some help. It COULD (not saying it is, again just trying different thoughts) be that she checked herself into someplace for help, treatment. that would explain the complete lack of communication, missing vehicle, etc. it is possible if this is the case, she could have explained this to the kids...they are old enough to understand some of it, and they are also old enough to keep it quiet if their mother had asked them too.
I Know many of you will vehemently oppose this, but I would hope that if I were going through all this and became concerned that I was slipping, I would hope I would have the intelligence and the guts to go ahead and get help so that I could face the coming divorce and anything else with confidence and inner peace.
If nothing else, this senario gives me hope that Gail is ok, just getting needed peace for herself, Matt did not do anything sinister, and even that maybe the kids are not suffering as much as we might think, because they have knowledge of what is happening. It may seem far fetched, but it fits as well as anything else we have heard and it gives hope that all could be ok.