I'm so sorry to hear this. It's really disappointing. A range of emotions are experienced during an ordeal with a life threatening illness, but I can't imagine how this could happen. Life is crazy, no doubt about it. I've heard of caregivers leaving, which I can't fathom either, but this is really unfortunate. I'm sorry you've been put through so much.
Dave

Mom's caregvr. DDS failed to dx 01/03. Dx Stg IV SCC 05/03. Induct. chemo, IMRT, 5FU, H, Iressa, Neck disect, radiation. Dad's caregvr. Dx 01/04 Ext. Stg SCLC. Mets to liver/bone 08/04. Died 11/12/04. Mom tongue CA dx 06/13, hemiglossectomy (80% removed) 08/13. Clean margins and nodes, but PNI. 6/15/15: Tongue CA at base of remnant tongue. Declined further tx; hospice.
Died 10/13/15. What a long and difficult journey.