dowry harassment and desertion

hello! my niece got married on 4th of september 2014 in India to an NRI from UK. the alliance came through a friend that her father knew.firstly her father didnot accept the proposal but later he let his daughter and the guy talk over the phone. my niece liked him and agreed to marry him . girl's mother refused because she had enquired some people about the family and opinions were negative about them. but the girl believed the guy as he told her that he will look after her very well and her father did not have to give any dowry or money ,but the guy's mother wanted only the wedding to be arranged which cost over 10 lakhs and jewellery. he and his family who are living in india were pretending to be very nice and decent.all went well and they got married. the guy went back to UK on 7 th september. first week of october she received a message on social media saying that the girl has to ask her father to give what all his mother demands her father to give or he wants to be separated from her and the guy does not want her going to UK to live with him. his mother wants a furnished flat,precious metals and cash.the guy also refuses to talk to her father. my niece is feeling devastated.we feel his mother has blocked him from talking to our family and sisters have brainwashed him.should we send him and his family a legal notice as they are not ready to talk at all but purely "money minded".