Difference of opinion with wife of six months

Writing for my nephew. My nephew had thyroid cancer at the age of 16 and had complete removal of thyroid. Thereafter 10 years he had normal routine check-up once a year. After 11 years doctor advised that no more he need to undergo the test and he is completely ok and only thyroid replacement to be continued life long. Due to the major surgery marks, he had grown up as an introvert without much socializing and did his Bsc IT privately and is assisting in his father small time contract business. On 14th September, 2014 my nephew got married officially in the church in Mumbai. We selected a girl from a very poor family so that, she also get a life also she loves my nephew with all his limitations. The proposal was initiated by her Uncle & Aunt, who stays at Ambernath. Her uncle and aunt was aware of my nephew case history. Before, marriage everything was informed to the Girl and her family about all the case of my nehew. After their approval, we had done a grant wedding and gave 30 thola Gold and everything whatever was needed for the marriage, including their two and fro travel, stay, cars at their disposal etc. Immediately after the marriage, my nephew gifted her an expensive mobile. also brought for an Activa. Within no time, this girl started to pressurize my nephew for buying a flat in Kerala, send monies for her sister's studies, pay off her educational loan amounting to Rs.8-9 lakhs etc., and started fighting with my nephew. We had fixed her on a job with Hiranandani Hospital and had advised her to work so that she can support her family and no need of wasting time at home since she is a qulified B.Sc Nurse. However, she left the job abruptly in one months time. In the mean while she was constantly chatting with a boy on FB and What-sap, which was bothering my nephew a lot but he suppressed without showing to family members however, by November 2014, he developed a severe depression and mood swing for which we had to take medical assistance from a psychiatrist. When my nephew confronted her, he deleted all the message and also a photo of this boy with her from FB. Thereafter, he had improved and both had gone to native place very happily. Back again in Mumbai she started fighting for anything and everything at last, she called her father from kerala and left home saying she is going to collect her Nursing Certificate. Thereafter, my nephew went to bring her and she didnt come with him saying will come by by 20th of April. However, since, then she changed her sim given by us and not taking any calls from our side. again my nephew is into deep depression and doctor advised we may have to admit him for observation. We are unable to understand how to go about this now. Can you please guide how to go about this case? just worried a lot for my nephew