Debbie, I'm so sorry that your baby is going through this. It's so hard to watch a pet suffer.
The decision to keep him at home for a natural death or taking him in for euthanasia is not an easy one to make. From the description that you're giving me, it sounds like your pet does not feel well at all and that he is in some degree of pain. When the body stops taking in food and water, organs will eventually begin to shut down. And that, yes, can be painful. Many times when pets are not feeling well, veterinarians can diagnose the problem with some bloodwork and other diagnostics such as feline leukemia/feline aids tests, radiographs, etc. If he's not been drinking at all for the past few days it's likely that he's dehydrated and would benefit from intravenous fluids. If you feel that your pet has reached the end of his days and it is his time, the most kind thing to do is to take your pet to the veterinarian's office for euthanasia. In comparison to a "natural" death, euthanasia is painless. The medication that is given is actually an overdose of an anethetic...it's literally as though your pet falls asleep and does not wake back up. Once administered, the medication's effects are almost immediate. I know it's not an easy decision, but it's truly the only way that you can ensure your pet does not suffer at the end of his life. Without knowing if there are underlying problems for your baby boy, it's difficult to be certain if he's in pain---but with him being vocal, ataxic (problems walking) and having a blank stare--I'm sure he's not feeling well at all. As far as your other cats knowing what is wrong with him, I'm sure they're aware of him not feeling well. Obviously, cats can communicate through vocalizations and body language. It might be expected that your other cats may be frightened of him at this time or they may try to comfort him. I'm sure they're aware of a change, although they may not be aware of an impending death.
Rest assured, Debbie, that if you do seek to have him euthanized that you should not feel guilty at all. It's a peaceful death and good decision to make when you feel your baby isn't going to survive. We cannot ever guarantee that a natural death will be painless. But with euthanasia, we can.
Let me know if you need further support in this matter. If my answer has been sufficient, please click accept. If not, reply. I personally don't get paid for my time unless you click accept. Thanks so much and good luck, Debbie.
Sami
Veterinary Nurse
8 yrs experience with animals, 3 in emergency med. Owner of 3 APBT and 3 sphynx