If it were me, I would immediately start putting plenty of colloidal silver in the cat's drinking water, begin giving the cat inositol/IP6 and oleander extract (either homemade or in supplement form) and make up a topical ointment using oleander extract, iodine, colloidal silver and DMSO. Try to find some oleander leaves (and flowers if present this late in the year) on a plant that has not had pesticides applied to it and then follow the instructions here:
Here is the formula for a very good topical ointment:
For a basic oleander skin cream, slowly boil the original brew down to a light syrup, condensing the liquid and making it thicker at a less than boiling temperature. Mix the final syrup with an aloe based hand cream, using one part oleander syrup to three parts hand cream. Used regularly, Dr. Ozel’s patent says this is a good topical cream for pre-cancerous skin cells, age spots, moles, and psoriasis.
For a truly superior skin cream, use ozonated olive oil instead of the hand cream, add in some concentrated (via boiling or evaporation) quality colloidal silver, iodine and several drops of DMSO. A word of caution: be sure to store the skin cream in a glass or ceramic container and be sure to thoroughly wash your hands before applying the skin crème. DMSO is a powerful penetrant. It will dissolve ordinary plastic containers and it will also take anything on the surface of your hands and skin deep inside with the skin cream.
Note: oleander skin cream is not like the zinc based black salves, which are faster acting, but can also be quite caustic. For the oleander based skin cream to be effective, it much be applied two to three times daily consistently and one must be patient as it may take a couple of months or longer to completely resolve the issue being addressed.
In addition, you might try alternating the above ointment with a paste made up of baking soda and water, as baking sode has had success against cancers it can come into direct contact with.
Colloidal silver and inositol/IP6 have both been very successful in getting rid of tumors in pets and oleander has had success against just about all kinds of cancers.
Please note that the oral doseage for a cat should be much smaller than for your average 150 pound human. I would start out with perhaps 1/8 or less of a teaspoon of the homemade extract or 1/16 of a capsule of the commercial supplement once a day and then gradually increase it up to perhaps one to two teaspoons per day of the extract or 1 capsule a day as tolerated.
Good luck with your kitty. Fourteen years old tells me that you have been a caring and good provider and companion.