Can you contact her GP and talk to him about it? I had to take over my mom's care and would meet with the doctor to discuss things after her appointment. Bless her heart, one of her appointments she complained of hearing music in her kidneys. The doc and I had to restrain ourselves to keep from laughing. But, he worked with me in her care. Does anyone have a power of attorney for her in case she gets worse off?
You have to distance yourself from her until you knee is healed. All that added stress is really bad for your healing. Talk to the rest of your family and explain that this in your time now and they will have to take over for you concerning your mom. Good luck. You have my prayers!