Legal Question in Wills and Trusts in Maryland

Re: mom left no will /but grandmother did

It depends on how the property was jointly held when your grandmother passed away. If your mother had a survivorship right in the house, then your grandmother wouldn't have had an interest to devise by will when she died. If your mother did not have a survivorship interest, then whatever interest your grandmother had passed to you and your sister by her will. Whatever interest your mother had at her death (either the whole thing or only that which she retained after your grandmother's interest passed to you and your sister) would be resolved by the law of intestacy. In MD, it's roughly split 50-50 among the surviving spouse and the surviving children.

Re: mom left no will /but grandmother did

Much depends on how the title passed to your mother, if at all. Title may need to be filed in order to vest an interest. It is possible that your mother's spouse takes an interest.

First thing I'd like to see is chain of title to the property. I'd also like to know why the will was not probated. Equitable interests are also relevant.