Now based on your history, your lad's behavior is a clear indication that there are adverse conditions making him uncomfortable toileting outside. In cats, this can be due to perceived vulnerability when toileting outside and colder weather making them less keen to going outside to toilet. Further to these triggers for cats moving the toileting habits indoor, we often see this in older cats like yours show this behavior linked to deterioration of the senses (if they cannot see or hear as well and therefore cannot hear approaching potential attackers), arthritis (since positioning is more of a strain for them and they cannot react to any attacks at the vulnerable time a quickly before), and when a bully/dominant cat is using those moments of weakness to attack the cat. As well, with the aging issues (arthritis and decreased senses), we can see these cats even struggle to use the cat flap and this too can reduce their success in going outside to toilet.
With your lad's situation, the best thing to do for him would be to give him a litter box in the house. You could even put this by the cat flap or where he is showing you he is comfortable going (if practical). This would be a protected place to toilet where he can go without fear of vulnerability. It will also be a warmer site, so as the winter temperatures plummet he will not have to aggravate his old joints to go outside to toilet. And if you do offer him a box, I would note that it'd be ideal to use a low lipped one with a non-pebbly litter (ie paper, wood based, sand, etc). The reason is because these considerations will make it easier for him to use the box if his joints are becoming a problem.
Just to note since he is an older lad and arthritis is all too common at his age, I would note some joint supplements that would be worth trying with him. You may find that if his joints are letting him down and causing this withdrawal into the house, addressing them could restore his going outside to toilet. In regards ***** ***** stage cats, we often will use supplements as opposed to drugs. One option is Omega 3+6 fish oils as they have anti-inflammatory properties. In regards ***** ***** we tend to give this at a rate of 20mg per pound of their body weight. Another option you can use glucosamine/ chondroitin with your wee one. These are a nutrient supplement that is available at your vets, pet shops, and health food stores (as as capsules, liquids, and even treats). They work to aid joint suppleness by helping cartilage replenish itself and blocking enzyme destruction of cartilage in the joint. Often we can find this helpful in animals with mild signs of joint struggles like inappropriate eliminations. Normally we give kitties 50mg glucosamine + 15mg chondroitin a day per 10 pounds of body weight. So, these would be worth consideration here.
Overall, your lad is telling you that his usual toileting site is not somewhere he feels comfortable going in. It may be due to a local younger cat bully encroaching on his turf that he cannot drive away or it may be that he feels his senses or joints are not as robust as they once were. Therefore, consider the above supports for him but to prevent this behavior from becoming an out of control habit do consider compromising with him and giving him access to a litter box at this point.
I hope this information is helpful.
If you need any additional information, do not hesitate to ask!
All the best,
If you have any other questions, please ask me – I’ll be happy to respond. Please remember to rate my service once you have all the information you need. Thank you and hope to see you again soon! : )