Does anyone have any thoughts or theories as to why Bob's SiL would have been surprised, I guess, to find Bob's housekeeper waiting at Bob's door?
One must wonder that if Bob had chosen, that day, to call his housekeeper in to clean up before Fontelle's arrival, that he would have also told his SiL (who we would assume was on-site to complete expected repairs) to expect her arrival. It would appear that perhaps Bob did not get a chance to tell his SiL that she would be arriving. Or perhaps he chose not to do so -- who now can say? Either way, I doubt that Bob would have treated that information casually. He was not suffering from dementia (as per his doctor) and he had chosen to call his housekeeper because he wanted things to be right for his wife.
I realize that there are a lot of details to balance out, but I keep thinking: Considering that Bob was sharp as a tack, and in light of the fact that he had already arranged to have his housekeeper come and tidy up his place for his wife, would he not have ensured that someone would be able to let his housekeeper in?
Why would he not have told his SiL to expect his housekeeper? And since he did not tell him, why would he leave?
IMO as with all of this post, he did not leave on his own accord, nor did he leave alive. I have to guess that the signposts in this case are pellucid to any LE dedicated to this case.