My mum and dad had mirror wills, dad passed away now. The

Hi, my mum and dad had mirror wills, dad passed away now. The wills stated that their home and all assets would be split 50:50 between me and my brother when the remaining parent passed on. My brother has now moved into the property having sold his own property, kept the proceeds from that but said I would never be able to sell the property as he now lives there and is a "sitting tenant". He was originally selling his own property, we agreed a valuation of mums at todays prices and he was going to buy me out early. Mum was going to write a new will to ensure then he had the whole property left to him. But he has kept all the money from his sale and refused to share. He now says, that my dad wanted him to have the house and my mother now says that as well. I just wanted to know if I could enforce the sale when my mum eventually passes. Something I never wanted to have to do. Thank You
JA: Have your brother and the mother and your father talked to a lawyer about this? What country do they live in?
Customer: UK, Dad passed away in 2019, my mums memory is fading and does not even remember the original will that was years before dad died. My brother says dad was not fully aware when he signed the will. But the solicitor came to the house and we even had to leave the room, when he talked to both mum and dad to ensure they were happy with what they signed and that they could make their decisions. Especially as we were doing power of attorney at the same time for the future. He explained that if for one minute he thought they were not capable he could not legally draw up the documents.
JA: What steps have they taken so far?
Customer: none, he has just moved in and said , this is my house, I live here now, dont care what the will says, you cant enforce a sale
JA: Is there anything else the Lawyer should know before I connect you? Rest assured that they'll be able to help you.
Customer: I think thats all,Customer: Chat is completed