My Mother Passed Away Two Weeks Ago And I Have

My mother passed away two weeks ago and I have her 11 year old female chihauhua. The dog has suffered from esophageal spasms for about 4 years and my mother spent on her care until the vet told her there was nothing left to be done. The spasms have gotten more severe and occur more often. She goes rigid from head to toe and I fear she is going to die each time. My mother wanted the dog put down and buried with her since the dog has been so sick but my brother and I just couldn't do that. What do you suggest to help her? (She is also blind in one eye and doesn't hear well.)