Regarding wasiyat

My father made last will before his death 3 year back. he clearified he marriage2 times ,after 1 st wife death. he re marriage . from his first wife he had 1 son, 3 daughter, in them one of death ,only 2 daughter and a son left. from 2 wife he had 2 son and 2 daughter , one son is mental retarded.all are married having there own children . my father had shown 3 property in his will . 1 st property on his elder son . 2nd & 3rd property on his 2 nd no son ,and 3 son which is mental retard ,which is along with 2nd son . tese property 2 nd and 3 rd in the passion of 2nd & 3 rd son. all the sisters work like mayara etc.all are done by 2 nd son. 2nd son and 3 rd son allways live wth his father 1 st son was seprated 35 years back. in property of my father problems ocuuring now is 1) will doesnt registered nor notary, having only 2 wittness. 2) Need new electrycity Commersial connection ,but 1 st son send him notice to dont give ,by giving excusse he have part in this property.but the property is 2 nd no . 3) 1 st son send notices to all tenant that he need 3 rd part of rent in his bank a/c. which lives in property of 2& 3 son 4) 1st son also be a party in between 2nd son and shop tenant to delay the case as also owner in that 2 no property. but 1 son has recived only 1st property in will. the case is running in court. what to do all these faces the problems? please advise me 2 come out all these problems. any judgement regarding to this thanks and oblige 2 nd son