We don't hate you for spraying her and it won't hurt her (and may make her hate you), but a noise-maker like a can of pennies may work just as well. Can you try to just walk purposefully to get to the food, water and litterbox, ignoring her until she gets used to you? Spraying Feliway on her favorite spots might help calm her.

Yes the family should take her in, but I can see how this would be difficult/impossible until they are able to regroup after your friend passes away.