a few alzheimer's issues... but most of us "old ladies" not only feed the critters, we pay out of our pockets (along with the help of low cost spay/neuter clinics) to have the ferals neutered. I did 6 on my own on a street we had recently moved to, and then discovered someone else up the block were doing the same to those in her neighborhood. This is in addition to all the ones we trapped, neutered, and released in the last city in which I lived. I say for most of us, whether ferals or our own indoor cats, all are treated with the love and care they deserve.
But I do agree that as people grow older, the tendency to horde becomes worse.. especially for those who had tendencies before the marbles started rattling (at least, that's how I describe myself)... that's why it's really important if you have a large colony around you, check out the rescues in your area and let them know. They have experience dealing with situations like this.
Of course, I have 9 cats and one dog as big as a pony. All are up to date on shots; it seems like we have one in to see the vets every month, at least. But then, mine are all getting up there in age, just like me. Into their high teens now (I lost three last year who were 21, 22, and 23 years old). I will admit as I get older and living only on SS these days, some months they eat while I make do. But I wouldn't trade my situation for love or money. They were all throw-aways or ferals, and the amount of love, companionship, and comfort they've given me makes up for any hardship I might experience.
I feel sorry for your neighbor. My mom lost one of her cats as she was moving into long-term care. We brought the other one home with us. I know she was so lonesome for mom; we even took her up for them to spend time together. Mom's spirits were always raised once she'd spent time with Micki. Micki would be great for the next couple of weeks, but then become depressed, even with the zoo around here and the love my hubby and I gave her. Old age is just not pretty for so many, many reasons. It takes courage.