Really good advice from Herschel and Rubylove. Your husband trying to calm her is only reinforcing the behavior. It's like a reward, all that talking and cooing etc.
So, until you get a behaviorist (who uses gentle methods) I suggest that you both be pretty aloof with this dog. Don't set her food bowl down but hand feed her. If she knows anything, like "sit," ask for a sit and give her a few pieces of kibble. Do that throughout the day rather than giving her the whole meal in it's entirety at one time.
Make her earn her resources (toys, going outside, coming inside, food, treats, attention of any kind....whatever is important to her) and see you and your husband as he leaders. Does she want to go out? Sit first. Does she want a toy? Sit first. Does she want a pat? Sit first. Do give her a treat for good behavior.
With the crate, during other times, besides when it's time for bed, I'd encourage her to go in, and you can sit in a chair next to the crate, reading (or something) Just sit there for 15 minutes or so. When she is quiet and "nice" toss in an extra yummy treat. And just continue sitting there. Don't close the door. Let her come in and out if she wants for now. If she stays in there to chew on a toy or just rest, hang your hand down by the door after you've done the treat thing several times. Do this every day a little bit. When she stops making a fuss, try closing the door, then open it again and sit there some more. Only reward her or speak to her when she's quiet. If she growls, snarls or anything like that, ignore her. Don't look at, don't speak. Maybe something bad happened in connection with going close to her crate or closing the door....maybe something frightened her at one time. Could she have been punished and put in her crate with the door slammed or anything at any time?
What else does she not get her way about that she growls at? You need stop reacting to her when she wants something that you don't want her to do or have. What about furniture? Does she growl when you want her to get off or anything? All the things she likes need to be earned. And when she wants something.....whines, barks, growls, you need to stop reacting to her in any way. Don't look, turn your head to her, speak. All that reinforces bad behavior.
Make her earn it by sitting or coming when called (if she knows those things) Don't do a lot of talking to her when you walk her. But reward her for good behavior.
A little deprivation makes a dog need you more and look up to you as her provider. So, if she is a little hungry (don't go to extremes) food will increase in value. Get her to need her leaders more. Your being somewhat aloof will make her need more socializing. (if she's always liked that before) Get her to want it. When her behavior is good, let her know how nice a little gentle socialing is...nice pat, treat.
I don't know what has caused this so don't rely on my ideas to fix this. Get a behaviorist to come observe. This is just what I'd do in next days...to get started before you get in a behaviorist to really see what's going on.
Let us know what you find out. I hope your sister will go for the idea of some professional help. Because without it, this little dog may indeed end up having to be put down. What a shame. Best wishes.