It was never said clearly .. but I believe he definitely meant that virat should marry his daughter Sai .. there is no other way in Indian scenario for any man who is not a blood relative to take guardian ship of a young girl ..
if they had not married Sai would have been tarred in a different brush with just virat coming to meet her in hostel ..
and also with jagtap still alive abd his family free .. there was another big danger for Sai .. he was about to die .. had the guy feel he would not live so he did it in the best way possible by handing over his daughter to his student .. who he trusted could protect her .. he felt he could demand this .. because he had sacrificed his life to save virat’s ..