After letters of administration

Hi all! my sister died without leaving a will and her son has gained letters of administration .Is there any way that you can find out how he distributes her estate as he is great at withholding information . My sister owed me quite a lot of money .My nephew has told me in no uncertain terms that it is up to him if he pays me my money or not . Some of the bills are actually rates and builders bills which we submitted copies of to the solicitor dealing with the estate. (Who we had to find out who it was ourselves because my nephew wouldn't freely tell us !)Advice please

After letters of administration