Desertation of wife by NRI husband after the wedding

We got our daughter who happens to be a doctor married in December 2020 to an engineer NRI working in the USA. He left to the USA in the second week of January. My daughter was supposed to be traveling along with him but he canceled her ticket as she was to appear for USMLE step 1 exam at the end of January. He told her to finish her exam n join him. But the exam got canceled due to the pandemic n snow storm in the USA. She wanted to go to her inlaws n they stopped communicating with her and gave a lame excuse that they are not free to welcome her to their house which is in another city. We live in Hyderabad. Now that the date for her exam is not yet announced, she wanted to join her husband n he refused to accept her. My son in law n his parents totally stopped communicating with my daughter n us since January last week. This is a proper arranged marriage n the groom was such a perfect gentleman that our whole family n relatives couldn't find even a single fault. He was just perfect. Last week he called us n broke the news that the 2 families have some trust issues n that he is not emotionally connected with my daughter to continue the relationship n announced that he is calling off the marriage. Our whole family is in shock. His mother has been pressurising him to do this. After the engagement, they had shared their expectations with regard to dowry to the mediator n the mediator discouraged them to demand. Now my daughter is heart broken as there is no communication with their family n we really are clueless about how to go about the situation. We belong to respectful upper middle class n terrified about the society too. Kindly advice.