#1: Start tracking everything! If you think it is time that she be removed, then you have to have a paper trail. This will keep you from having trouble.
#2: You need to look up policies and procedures for your facility about actions you can/want/need to take with this person. What steps to take for discipline. Verbal, written verbal, 1st write up, etc. Follow them to the "T".
Start by having a conference with her about her attitude, actions, inappropriate statements to the residents (State CAN hold you responsible for her actions...) etc. Make a list to cover everything at one time. Ask her why she is not happy in her position, give her a time frame to work on her issues and schedule a follow-up conference with her. Make sure she gets a copy of the policies, all the items you go over with her, etc. It seems like a lot, but it is more professional and will show her you mean business.
Have you ever had a management class? If not, get a book, video, take a class, whatever works for you and your schedule. It is essential to understand the various aspects of management. You ARE a manager.
If the person cannot conform to what you need as an assistant, then you will have to let her go. You need an assistant that will support you and your program in a positive manner. Activities in a facility are extremely important. They help with the quality of life for the residents. If she cannot do her job, you do not need her.
Look at it from a marketing point of view: You could lose a potential resident because of her! If a family is touring the facility, sees her and does not like her attitude and treatment of staff/residents, they will be turned off by her. NOT A GOOD THING!
As for her threatening to quit: no one is irreplaceable...
Hope this helps.
If you need more ideas, e-mail me!!
cdebord@sbcglobal.net