Sandra Boss was a victim there is no doubt. To be married to a man for 12 years only to realize that you don't know him, don't even know his name.
But IMO she was an extremely lucky victim. She learned about his alias's, possibly learned something about what he was up to. There have been many cases when women in this position are killed or go permanently missing. I think the idea that he intended to use his daughter to get money from her is entirely possible.
Yet, Boss still isn't bad talking him. While her daughter was missing she didn't talk about the alias's and LE didn't release the info either (I hope they knew.) This info didn't get out until Snooks had been found and it didn't come from her. To me that seems odd. I would have been shouting the fact that he was known to use alias's, that he could be living under another name. Anything to help find her.