From what you say I infer there are no loose stools now. And the present problem is he does not eat well.
Did he have problems with cow`s milk before this? What tests you had done in stool? Was stool occult blood done?
During diarrheal episode its good to stop milk, but curd should be given in plenty. Curd has probiotic
bacteria naturally. Give him lots of curd.
Do not force feed him. Give him what he likes. Try to offer him rice based food, vegetable soups, boiled potato, banana, curd, porridge made of rice/ roasted bengal gram/sago. Give him small quantities of food frequently say 6 times a day.
You may give him soya milk too.
And how many leukocytes
were there in urine? Urinary Tract infection
in kids can also present with loose stools. If doubtful have urine microscopy repeated. Urine culture can confirm the presence of infection.
How is his activity? If its okay and he has no other problems, you need not worry. He will be okay soon.
Hope you find my answer helpful.