You might want to try looking for cat ‘sanctuaries’ where cats are not adopted out, but live out their lives. If you could find such a place and donate for their care, that might help them accept your cats. The other thing is that the cats are elderly and won’t be living as long as a young cat.
There’s a sanctuary in NJ called Tabby’s Place - they generally don’t take cats from the public; however, it appears they might be helpful in providing you with resources/help for ‘your’ four cats.
https://www.tabbysplace.org/about/
From their website (intake policy):
Although we wish we could help every cat in need, we unfortunately cannot generally take cats from the public. But, if you’re seeking a home for a cat, we can help you in one of three ways:
Our Help Form will connect you with advice, resources, and a list of organizations that may be able to assist you.
The Guardian Angel Program enables you to plan ahead for your cats to come to Tabby’s Place if you should predecease them.
The Exceptional Circumstances Program is for folks who are seeking to place a cat at Tabby’s Place immediately, and prepared to make an extremely large donation that can help many other cats.
If the cat you need help with was adopted from Tabby’s Place, please see our Return Policy.
Whether or not we can take your cat at Tabby’s Place, we can help point you in the right direction. You’re not alone, and there is hope.
++++++++++++++++++++++++++
I know there are other cat sanctuaries, but finding one is going to be the trick - most are very well populated.
Excellent advice. We have a cat sanctuary in our. town run by a very nice woman. Two of my friends adopted adult cats from them. I buy them cat crunches in big bags once in awhile.
Also, vets will help . My cats’ only vet at “The Cats Meow” vet clinic was happy to place two cats, a bonded pair, for a friend. Posted pictures gave them shots,, made sure they were healthy before adoption. I feed an outside cat abandoned when her owner died and my vet will give her free shots and post her picture as “available”. I’ve already found a neighbor who will take her if we can get her into a crate. Big IF.