Neulasta and Insurance Issues

I've been trying to stay positive throughout this whole journey with my mom (Stage 4 Colon Cancer, mets to liver and lungs) and she's been doing well, but when we went to her 10th round of treatment this week, we found out her Neulasta was not covered by the insurance anymore. 

Her Oncologist and the second opinion Oncologist I talk to when I have questions both said that we will move forward without it and she should be okay. 

Her mouth was getting quite dry and the Oncologist had decreased her chemo dosage before her 10th round of treatment and I think the insurance company saw this as an indication that she doesn't need the Neulasta and apparently they can deny it.  She only has two more rounds left of treatment and I'm so upset that I can't do anything about it. 

I don't want her to get a fever or infection for not having this injection placed on her arm to keep her white blood cells count up. It's currently high right now, but I don't know what will happen a couple days from now. 

It doesn't seem like the Oncologist is going to file an appeal. The fact that this is an insurance issue is just bothering me so much. I know this happens all the time with various cases, but it's just so frustrating. 

Any thoughts would be appreciated. Thank you.