Legal Question in Wills and Trusts in Pennsylvania

I do not understand what is going on. If your mother and grandmother owned a home, is the grandmother deceased? Did they own the land as tenants in common or as joint tenants with right of survivorship? Review the deed to see if it contains the magic language creating a joint tenancy with right of survivorship. If it is there, then the land would pass to the survivor automatically. If your died, then it passed to grandmother if she is alive and when grandmother dies, it will pass as per grandmother's will.

If grandmother died before your mother, then your mother would own the land and the property would pass to whomever is named in her will or, if there is no will, as per the state intestacy laws. I assume your mother and grandmother and the property in question is all in PA. If not, real property is governed by the laws of the state where it is located and the intestacy laws would be in whatever state your mother and grandmother lived at the time of their death.

If mother and grandmother owned as tenants in common, then grandmother's share would pass as per her will or via the intestacy laws if she is deceased. Same for your mother's share.

I would have to see their wills to know who would inherit their shares.

As for the affidavits, what are you talking about? Why would your siblings have to be present? Your sister can make an affidavit and get it notarized. If she got affidavits for the other heirs, then they have to sign the affidavit and get it notarized on their own. It sounds like your sister may have forged affidavits and filed them with the court and the affidavits say that your sister can be executor of your mother's estate. If this is the case, don't waste any time here, but get up with a probate litigation attorney immediately in the state where your mother lived at the time of her death.

Either there is or is not a will for your grandmother. If grandmother had a valid will and it named you, then you are the executor. An administrator is where a person dies without a will. If you are the executor, it may be wise to also get an attorney to assist you with the probate of your grandmother's estate.