It was odd for me that in the bts she is the one talking to the doctor - or rather the doctor is talking to her. So he actually thinks she is his wife.
Dont know if Mohan looks like he is in his 20's or she looks to be in her 30's for everyone to goof up. Well... actually they can look their respective ages and still be called couples no doubt, but i don't think that would be the default assumption everyone would make.