Congratulations! I hope both mom and daughter are doing well.

I have no had anything similar, but you might consider trying Feliway spray or plugins (maybe do plugins- if you're too liberal with the spray, it can give you a whopper of a headache). It's made up of pheromones that help calm cats, and it did wonders for my friend's cat when she moved. Perhaps if your wife's cat feels calmer, she'll be less inclined to be so concerned about the snake possibly being out and about.