While I commend you for getting your cat through his illness, I strongly question your internet guided diagnosis. The diagnosis of feline distemper should only be made by a veterinarian and no mention of a vet visit is made on your web page.
The symptoms of feline distemper include vomiting and diarrhea. The state of the digestive tract when infected with this virus is horrendous and often the lining of the intestines is sloughed. Oral food and water would not be reccomended and antibiotics are usually necessary to prevent bacterial infection in the bloodstream. Successful treatment of this disease requires veterinary care and usually hospitalization.
Tube feeding is a technical procedure that should not, in most cases, be performed at home. It requires skill and knowledge and should only be performed by a trained professional or under the direct supervision of such a person. There are many complications that can occur while tube feeding including aspiration of the liquid diet, aspiration of the tube, pneumonia, ingestion of the tube, and death.