Fourteen isn't a bad stretch for a cat, and I know it is hard to let them go, but sometimes it is the best thing to do.
My boss just had the same thing a few months ago her 15 year old cat had stomach tumor, the cat got awfully cuddly and just liked to sit on anyone who would be in the chair long enough to perch on, get a scratch under the chin and purr her guts out, something she would not normally do. She had the brother to this cat as well, and had to have him put down due to renal failure a few years earlier. She said that they feel now that they let him linger too long before doing so and were not going to let this happen again.