I dont think prem has had an opportunity to find out how nandini is, he has always seen her troubled, in fact he has troubled her since the time they met, he caused all the drama in her household for their marriage then there was all the tension at the marriage, there was like one day when nandini was not bothered by anything... in fact even then she had to deal with gautam and urmila, specially compared to sumati who has grown up with nandini,
now however i hope he does pay more attention to her discomfort specially when she is around krishna, Gauravs character as abeer was naive about Omi for a very long time and would hate to see prem continue his friendship with krishna in the same manner....