Estate Question?

There is not a 'one size fits all' answer for this. It depends on specifics none of us here know anything about. Whoever the executor of the estate is needs to be discussing this with the attorney they retained to represent the estate. If an attorney was not retained, big mistake. The executor needs to get one ASAP.

This can't be answered without knowing the details of the LLC agreement. You need a lawyer.

Depending on how the LLC was structured, his share MAY automatically default to the remaining owners, or become a part of the estate that would be sold. In nearly all cases, the remaining owners would at least have the first chance to buy out his share.

This is an issue for which an attorney would have to do some research to determine the legal answer.

First, what they get depend son how the deeds are written and how the LLC is set up

They can't take it for debts unless he owed them money, which wouldn't make sense.

Ask a lawyer, and by the way, there is no such thing as a grandfather in law.

Have a lawyer look at paper work to set up the LLC.

The agreement establishing the LLC provides what happens to its members' shares upon death of a member.

His share of the LLC is sold to pay off the debts.

Heirs don't "inherit" the assets till after the estate's debts are all paid off. You can't borrow money and then leave that money to other people, not paying off the loan first.

Also the other members of an LLC are not automatically his heirs. They don't inherit his share at all, unless that is in the will.