Can one force an heir to the house to pay rent?

The lawyer is correct; rent should be paid. Yes, the executor can and should have a lawyer, whose fee is set by statute and is payable from the estate assets at time of closing.

Until the estate is settled and title to the property is turned over to the heirs or is sold and the proceeds are turned over to the heirs, the executor is within his or her rights to require any resident on the property to pay rent. A family member who is executor might ignore this but the attorney is ethically required to obey the law and do his or her best to protect the assets of the estate. It is possible that elder daughter is still the executor of the estate and the attorney is her agent in the matter. If that's the case, elder daughter may be able to direct the attorney to allow younger daughter and her children to remain rent-free until the estate is settled. The cost of the attorney should be paid from from the assets of the grandfather's estate.

Sorry, she owes the rent.

If the attorney is the appointed administrator or executor of the estate, he has a fiduciary duty to preserve the assets of the estate and can charge rent to the person living in the home. She is receiving a benefit by living in the home however the estate is also receiving a benefit by having her live there and taking care of the home. Who is paying the mortgage, taxes, utilities, insurance and upkeep of the home? You should be able to work something out with the executor that is fair and agreeable to all parties. Regarding attorney fees, typically the attorney who represents the estate is paid from the estate assets. If the will named an executor and an alternate, then any of the other family members who also resided in the same state as the decedent could have requested to be the administrator, even if they were not specifically named. The other beneficiaries are also entitled to hire an attorney on their own to make sure their rights are protected. I hope this helps.

Yes, as long as the house is in the estate, the estate has the right to charge her rent. The estate is not required to charge rent, if all the heirs oppose charging the rent; it's not necessary. Few executors have the knowledge and expertise to handle an estate without a lawyer. The lawyer's fees are paid by the estate and would be the same regardless of whether the relative is the executor or the lawyer is.

If an attorney is hired, that attorney obviously will need to be paid. If representing the executor/administrator, it is typically paid by the estate. If a beneficiary hired the attorney to protect the beneficiary's interest, then that is up for question depending on the facts and reasons. As for the rent, the person living in the place should be responsible for some rent. The Estate would be responsible for the taxes, upkeep, assessments, etc. But this is technically how it should happen. If everyone agrees to things happening differently and all beneficiaries sign off that they received everything they deserved upon the distribution of the estate, it shouldn't cause any problems. Things could even be adjusted to reflect the benefits received.