No access to land

We had a plot. there was a house in the middle of the plot. mother had given land in writing in her 4 children name. the house with a small part of land surrounding to house, were kept in the name of 2 daughters. approach road to home was kept as common for all. Mother had written an wasiyat showing all these. she further had given in writing too as elder sister insisted for her share of land. When mother were not well, and during the last 3 years, she stayed with youngest son in the same house. he had by force written the house and approached road in his name and registered the same by calling registrar at home. as mother was not in a state to go to registrar's office. no one were knowing all these. as he know if anyone complaints within 4 months of registration, this may not work hence he kept it as secret for 4 months. Before that mother stayed with younger sister for more time. even when mother were not well she stayed with sister. when sister wanted to accompany her husband, she had no other option but to leave mother with brother. Mother passed away last year, now he told us that road and house is his. and now there is no approach road for our part of plots. He is taking advantage from our plots too. we are unable to go there as no access. I needed a bank loan by keeping land papers, bank manager visited the land for inspection and brother told him that road and house is his personal. manager left the premises saying loan not possible as no access to property. I have been requesting brother to give a small part of his land to convert as common road access to our land, for more than a month now but not doing anything. at the entrance his land is there. after that my part of land, so road came through my plot but he has taken that part too in writing in his name from mother. Can anyone suggest what action to be taken so we gets access road. Only he is staying there, others are staying else where. This land is in kerala state.