OP, you need to hire a lawyer in the relevant jurisdiction. Did your parent hold their assets in a trust? If not, it seems the house will have to go through probate. Was the interest in the house addressed in a will? Get legal advice. There are laws that cover the situation.
In general
Co-Owned as Tenancy in Common: Probate Required
Co-owners sometimes own real estate as tenants in common; you might come across this form of ownership if the co-owners inherited the real estate—for example, they were siblings who inherited a house from their parents—or were in business together. Each co-owner can name a beneficiary in his or her will; if there's no will, the deceased co-owner's interest in the property passes under state law to the closest relatives. Probate will be necessary to transfer the interest in the property.
https://www.alllaw.com/articles/nolo/wills-trusts/transferring-real-estate-after-death.html