I lost my 6 yr old girl to breast cancer on New Years day. I don't know how long she was sick before I noticed something was off. When I realized my pair hadn't been eating well I took her out to give her a treat and found out her back legs weren't working.
When I took her to the vet he found a mass in her pouch area. He gave me some pain meds to see if they helped her walk better. I took her back a few days later since the meds did nothing. She had lost 10 grams in less than a week. Then he took x rays and found several masses which probably caused nerve damage, hence the lameness. He gave her Prednisone and that helped a lot. He had no other treatment for her at that point. I could have taken her to a Veterinary school for possible surgery, but decided against that.
I hand fed Piper a few times a day and she really perked up after that. She was a strong little glider, climbed all over the cage with just her front feet! I rearranged the cage to give her more resting spots and put extra pouches near the bottom, but she would have nothing to do with them.
She went from being mean and crabby to being sweet in those last few weeks that she was with me. After 6 years Piper and I finally bonded.
My story probably wasn't much help, but possibly someone else here has something to say on the subject. I will pray for you and Lilly.