Two things I think about tonight's episode and how things might turn out....
I think the wife does not have cancer. I think she might also have Munchausen's and Munchausen's by Proxy. She's very manipulative ('can't you see I've got cancer?' and being shocked that Boyd would speak to her irreverently, etc)
She said the husband Donald never went to hospital or the hospice so he wouldn't have seen the oncologists. There's a slim chance she may have passed the daughter's illness off in this way and actually poisoned her or something. The brother is ill as well I think (didn't he say so in the trailer for tomorrow?) and I also think he's being poisoned.
The other thing that might be waaaaaaaay off the mark but also may not be. Spencer was fiddling with a chain round his neck when he was asking the new girl about her past. It was the same chain as the black nurse had lots of in her car. 
what do you think?