my mother died 3-7-20 and my sister is holding the will and has not filed it in michigan courts-is there anything that i can do

Contact a probate lawyer who practices in the county in which your mother lived and died.  Some states require that a Will be submitted within a certain period of time.  Sometimes a letter informing the person holding the Will of this requirement prompts submission of the Will to probate.  Sometimes they claim there is no Will.  In that event, any heir can file an application for an heirship determination and settle the estate.