Forcible usage - Joint inherited property

We (our mother and two brothers A and B ,had been staying in the said society from 1986.My elder brother got married in 1998 and after few years started staying separately. I was staying with our Mother till some years of marriage (2001) and then moved to adjacent building in 2004. My elder brother,staying far away moved to this society in 2009 on rent to a different flat.On Jan 2015 my mother expired.She had willed that on her demise we share the house in the format " A and B will get 50% each and either party could take sole ownership by paying off the other party the market value,and till such settlement of the sharing, the flat will not be occupied by either of them and the executor/s will see to it in fair settlement as soon as possible,by securing a probate of this will from a competent court if required".We have not been able to come to a consensus on market price.We are two (Christian) brothers who are in the process of inheriting the house on the demise of our mother (transfer of share certificate applied for in housing society).However he(B) stated that since we have not been able to come to a consensus, he would move from the rented house to our mother's house which is vacant.He has started painting etc.Please advise options to prevent his complete control and take over of the flat.