I live in Northwestern Ontario, my mother recently passed…

I live in Northwestern Ontario, my mother recently passed away, and my father is the surviving spouse. I have an inquiry about my mother's most valuable and possibly her most cherished possessions, her jewellery. My father decided to transfer possession of all of my mother's jewellery to my sister without any consideration / consultation with the other 3 remaining siblings. He based his decision on a verbal conversation he claims to have had with my mother at some point in time, as to her final wishes about her valuables.
Shortly after my mother passed away on March 5th, my sister was uncertain as to what to do with my mother's valuables as there were no instructions written down as to my mother's final wishes. She turned to my father for some direction and that was when he instructed her to take immediate possession of all the jewellery based on that verbal conversation with my mother. None of the other 3 siblings were a part of this conversation and had no part in the decision on the 'transfer of possession' of my mother's valuables.
My sister who resides in Southern Ontario is currently at the family residence in Northwestern Ontario to assist my father during this transition phase. She is also the designated estate executor.
2 days ago I asked my sister about my mother's jewellery. She was not receptive to my question as if it were none of my business. She said she has the jewellery in a box and will be taking it all back to her residence in Southern Ontario. I asked her if anything was 'written down' as to my mother's final wishes and her response was 'ask dad', then she walked away.
To me this seems like a case of estate hijacking given that my mother's jewellery collection is very valuable (potentially mid, to high 5, to even 6 figures). In this situation, legally, what should be the process that is followed so the there is a fair and equitable transfer of possession / ownership of my mother's cherished and valuable possessions, given her final wishes seem to be ambiguous. Thank you.. Rob