The article cites the Laundries as saying they "were engaged to be married." That does sound like they were still engaged at the time, although a case could be made that it was past tense. IMO it's past tense though due to the fact that they are both deceased, or else it would've been more accurate to say they "had previously been engaged."
My own opinion is that I personally cannot fault the Laundries for Brian having been a scheming, sneaky dangerous murderer. Cassie seems like a regular person, and I don't believe in blaming parents for what adult children do.
What I DO blame the Laundries for is their cold-blooded refusal to respond to the Petitos' phone calls and pleas for information and help. That to me is inhumane. Gabby lived with them for a period of time and I would presume they'd be frantic for her well-being, too.
On those grounds I can see the Petito/Schmidt family suing for intentional infliction of emotional distress, although I have no idea if the Laundries knew in advance what Brian had done. I also understand that Gabby's family is desperate for all pertinent information, and in their shoes I would feel and do the same.
@Warwick7 it's so painful to be reminded that Gabby had written to Brian that he made her "life feel unreal." A life that he deleted from this earth.
Jmo