why does my father get all the house?

That's a difficult situation.  I'm guessing that the house was in both of your mother and your father's names as joint owners, so it became his when your mother passed away.  Your mother could have altered this form of ownership while she was living, but it cannot be altered now.  I'm also guessing that your father is receiving Medicaid assistance for his nursing home care and the state has learned that he has this house as an asset and so wants to force a sale and use the funds toward his care.  I would advise meeting with an attorney to pursue filing a claim of unjust enrichment against your father, claiming that you contributed a certain amount of funds toward the house (mortgage, repairs, etc.) and seeking compensation from him since he is now the owner.  YOu will need documentation of your contributions, and, if you have lived in the house, you may face a defense that these payments were like rental payments or even gifts to your mother.  Then again, if your father is in a nursing home, it is not clear who would defend against this lawsuit on his behalf.  Maybe you would end up negotiating some sort of settlement with the state Medicaid program division.  There also may be another legal cause of action available to you in PA, such as pursuing child support if there was an order for your father to pay and he did not do so.