cat's ear growth

hi i havean old tom cat lucky , hes around 15 or so. in fine health apart
from ear mites which hes been suffering from for years.2 weeks ago i noticed
a growth(greyesh mass which discharges white stuff and something like a
small capsule fleshy like ) inside his ear just below the pinna and booked
an appointment for the vet. he called out earlier today and gave me the
bleak news that this growth is something a lot of old cats get and in the
end it proves fatal considering his age an op was out of the question. i
asked how long has lucky got, he said it depends sometimes weeks sometimes
months .has anyone has any experince with this and what to expect.thanks for
any help