hi,

you did not mention you had biology in 10+2 course or not. the eligibility criteria for diploma in unani course is you need to have 10+2 degree from a recognized university and have to secure 50% marks in physics, chemistry and biology. The students who have the language Urdu in 12th class or having proficiency in Urdu language has given the preference in admission. there is not many college which offers diploma in unani courses in distance mood. you may follow the below link to know about courses,

http://www.alternativetherapycourses.com/unani-department.php