I would take him to the nearest Large Veterinarian College. The biopsy and treatment will be less expensive and they would know all the new possibilities of treatment. I have included the Merck manual text on this subject. In dogs, the 3 most common are malignant melanoma, squamous cell carcinoma, and fibrosarcoma. The gingiva and tonsils are affected most frequently.
Signs vary depending on the location and extent of the neoplasm.
Halitosis, reluctance to eat, and hyper salivation are common. If the oropharynx is involved, dysphagia may be present. The tumors frequently ulcerate and bleed. The face may become swollen as the tumor enlarges and invades surrounding tissue. Regional lymph nodes often become swollen before oral and pharyngeal tumors are observed.