Brucey fighting brain disease

For those who know me, know that this is very hard to do as I am not one to ask for help, but this is for my baby boy, who I would do anything for. Also for those who know already, I had to take him to animal emergency on Sunday after he had 2 seizures in about 12 hours. After $700 for bloodwork and three medications, and having to see a neurologist today which was another $170, I practically drained my savings account. Bruce most likely has an inflammatory brain disease, Meningoencephalomyelitis of Unknown Etiology (MUE). The only way to diagnose properly is through an MRI and spinal tap. This can cost anywhere from $3,676 to $4,024. This is A LOT of money for me that I clearly do not have, but I would honestly sell a kidney for my boy. We need a diagnose in order to properly treat, meaning his prednisone will have to be doubled in order to suppress the nervous system, and he would need Cytarabine, which is a chemotherapy medication to decrease the swelling in his brain and spinal cord. If undiagnosed, the worst can happen. Bruce is only two and for a chihuahua I was hoping he could live to at least 15 (my chihuahua Chewwie growing up lived to almost 19!) I am Bruce's third owner, but honestly, he has saved me. We would appreciate any help we can get, even if it is $5. If you know Bruce, you would know how lovable he is and the smiles he brings. I bring him to the therapy office I work at for pet therapy and he is very affective!
Thank you in advance!