13-year-old cat with recurring attacks

I hope it is appropriate to post regarding animals here; I got a sense from the message strings that it may be. In any event, thank you to all contributors for their caring and fascinating advice on all the topics.

Our 13-year-old neutered male street cat, whom we have had since age three months, has repeated episodes of what I describe below as "attacks".

Symptoms: drools copiously, often the saliva seems really thick, the fur around his mouth is sodden, he dribbles onto legs and tail when curled up resting; weakness and loss of coordination: spine droops towards the back legs, which stagger; suddenly stops and stares into space, seems disoriented, and then jolts back into movement after a few seconds; aggression / clinginess – jumps onto laps seemingly seeking affection and then clings on with claws and bites and is very hard to disengage, also bites / chews on / claws inanimate objects such as children’s toys; cold; condition has been accompanied by diahorrea. Becomes more and more prostrate, with great weakness.

Recurs every few weeks, can last for a few days with ups and downs, more than once I thought he would not live, but he survived, although he has never regained his full vitality.

He has been occasionally accident-prone since youth. Not sure what first started the cycle of attacks off, but he was diagnosed with hepatitis during our absence abroad for four months two-and-a-half years ago and treated conventionally. The hepatitis passed but he has never been quite the same again. His attitude to my family and I has changed greatly since that time. He seemed angry at us on our return home, and is standoffish and rejects affectionate advances, except when ill, at which time he exhibits the behavior described above.

Conventional treatment involved blood tests that ruled out a range of parasites and the usual feline diseases, the conjecture was that the liver was involved (due to the previous history of hepatitis) but tests suggested his liver function was not too off, apparently. Medication was antibiotics.

Seems to come on in the morning, but he roams and I seldom know when the attack started. He spends most of his time away, occasionally returning for food. He shares our home with two other cats, both of whom he dislikes and resents - he was an only cat for six years. He is not a great fan of our two children, either, and he ignores them.

Wet / humid weather may be making it worse, and the current cycle of bouts (he had a far milder series of such attacks about two years ago) started last winter, shortly after we moved to a new apartment (some three hundred yards from the previous one). Originally I thought he had a severe cold.

Seems to be better for undisturbed rest, at which time he seems to be better for warmth, but is periodically very restless. He often rests draped over something (such as the stabilizer wheel of my son’s bike) with his chest pressed against it, I wonder if this gives him some relief.

Both here and at our previous home he has adopted a nearby female neighbor, with whom he spends time in preference to us. They describe him as sweet and affectionate with all family members and visitors, in contrast to his behavior with us.

Usual diet is standard dry food, I have very little control over what he eats since he is generally out and about. Always liked fresh chicken and tinned tuna, and would chew through plastic wrap to get bread; used to be a very healthy eater but now very thin; barely eats during an attack, but drinks OK. Always preferred to drink from the tap / faucet, and during an attack finds it easier because he prefers to sit than to crouch over the bowl.

Details of any major diseases suffered in past.

No known reaction to medicines taken, and has not been vaccinated for some six years, but I have a feeling this may be vaccine-related, specifically the rabies vaccine, which he received for the first and last time some six years ago.

Nux vomica D30 seems to help greatly but has not cleared the condition up and it seems to be occurring with increasing frequency. He is unhappy and it is difficult for me to believe he can withstand much more of this.

I would be grateful for any suggestions as to continued homeopathic treatment. Should I simply persist with the Nux Vomica D30, for instance?