Help Timber get an MRI

Timber is a 3 year old, well loved Husky.
He developed seizures two years ago and they have been well controlled on phenobarbital up untill 2 months ago when he started having severe breakthrough cluster seizures.
Despite an increase in his medications, he continues to have horrible episodes and the vets caring for him are concerned about the sudden increase in his seizure activity as well as the fact they no longer seem to be controlled by medication. They really want us to do an MRI scan to see if a tumor or brain abnormality is causing the seizures as well as seeing a neurologist, however an MRI is very costly and we have already spent well over $3000 the past two months on his vet visits and medications. We have exhausted all our savings to help him get better. 
Unfortunately the vet said if we can not get his seizures under control we will have to discuss quality of life. 
Timber is my best friend and I love him dearly, I don't want to lose my dog at 3 years old, aside from his seizure activity he is a dog full of love and life and its been heartbreaking watching all these medications sedate him so bad that he spends most of his time sleeping.
I want to make sure we explore all possibilities and if a tumor or brain abnormality is causing the seizures we wont know without an MRI and we can't treat anything without knowing. 
Please help our fluffy guy and thankyou so much for taking the time to look at our story.