Problem with Fathers Will

Hi
My dad died in February this year, my sister is not giving me any details of the will. I do not know even if I am in it. My brother passed away and as he did not leave a will, it was left to my dad, he was in a home and my sister was made personal representative for my father and the estate went into her account, to be used for his benefit and use. My sister lied to me and said my brother left £50,000 but I have since found out through probate it was worth over £350,000. I believe she only told my dad that my brother had left £50,000. In the time my dad was alive, she purchased a new car, new expensive fully fitted kitchen, and numerous expensive items for her home.

Now my dad has died, I do not know what is happening with his estate, she is being very cagey, I know she took my dad to have him write out a will with a solicitor. She wont disclose anything, even the name of the solicitor, I think my sister made him leave his whole estate to her, because if he hadnt, the estate would have been equally shared between me and my sister, and I would have then found out that my brother had left over £350,000. I have not heard anything to say that I am in the will? I have tried probate and nothing has been found. My sister told me when my dad died that most of his money had been used up for the keep at the nursing home, she thinks I believe there was £50,000, and no way could £350,000 be used up in 15 months
in a council run home.

This is my dilemma, I think my sister has not put the remainder of my dads money into his estate and just left the £300.000 in her account. Has she broken the law by not including all his monies that was left to him by my brother? And in this case would that mean the money she failed to include still be classed as my brothers Estate? Do I have any right to claim half that money?

If my dads estate is not showing through probate does that mean there wasnt enough money to constitute it having to be registered with probate?

Thanks for your time