Do you have Power of Attorney for her? If not, consult a real estate attorney. Something can be worked out.
If mother's will gave her real property to her son and gave her nephew the right to live in the property then her nephew has a life estate. Her son must follow the provisions in the will. You should consult with the attorney who handled the estate to determine what your rights and obligations are.
The estate has that responsibility. Until the estate is settled, the house ownership and responsibilities have not been transferred.
A power of attorney terminates when the principal dies. You need to petition the probate court to be appointed the representative of her estate.
If the mortgagee neglects to record the mortgage then it will not become a lien on the real estate. However, you are still obligated to repay the loan.
While the estate is still open, the property will become part of the estate and will be distributed under the provisions of the will or as intestate property.
if she's ok with it but technically you're still considered a child.
If the loan is properly documented, the loan counts against their share of the estate. If there is not enough money in the estate to pay off the debts, they will have to repay the loan.
That could be a breach of fiduciary duties. However, if the grantor desired this to happen, it would be legal. It may still become a part of the estate when the individual passes away.
No, she is still a child. The parents are still responsible for her.
not if she moved out of the mothers house
Yes, the executor of the estate may do what they can to insure the value of the estate doesn't lose value. But the estate will need to file a tax return for the rental income.