Help save Diesel's life so he can keep saving mine

Diesel is my unofficial service dog. He has started bleeding through his nose for an unexplainable reason. We brought him to the vet and they sedated him and did xrays and bloodwork and the xrays showed differences between the two sides of his sinuses but is doesn't show what they are. He needs a cat scan and a Rhinoscopy to show if it is a tumor or cancer or foriegn objects or fungal infection. It is$5000.00 plus tax and the subsequent treatments are$1000.00 each as they have too do it under anesthesia and a scope. I cannot afford this and I am not ready to lose my dog. Diesel is a 5 year old German Shepherd Dog. I am disabled with spinal and neck issues. My legs give way and I don't know when I will fall. Diesel is always by my side. When I wake up he is at my bedside to catch me and help hold me up if my legs give way. He sits by my chair and pulls me up if I am not strong enough or my pain is too intense. He sits by my feet in the bathroom and pulls me up from the toilet. He wasn't trained for this he just started doing it when i struggled.  He truly doesn't deserve this and I can't help him.  Please help me to help him.  Thank you. I will post pictures as this develops so you can see how you are helping. PLEASE WE ARE DESPERATE TO HELP HIM FAST