Try starting with ne type of meat, either raw or cooked, maybe ground venison or rabbit, so it would be available and not too expensive. Your cat will eventually eat something. As far as litter, try using the pellets for a pellet stove, as they do not have a strong odor and are dust free. Homeopathic pellets can be crushed between 2 matching spoons and the powder dropped into the cat's mouth. Conventional drugs for asthma do not cure asthma, simply alleviate the symptoms, so it doesn't matter what the diagnosis is, as they are only treating symptoms.