My sister in law is the executor of the will. she hired her family members to do work.

do you have to be a licensed contracter to put a lein on a house that is selling, just a little history the house is in Houston Texas it is part of an estate witch has a will with 4 living heirs. The executor had over 20 thousand dollars done without any knowlede of the 3 siblings, Her daughter did 12 thousand dollars of the work. very questionable what was truly spent most i think is labor, she has no dba or contractors license can she place a lein on the property

A mechanics lien can be attached for labor or monetary expenditures.~

No, typically anyone who has a bona fide claim for materials or labor in real estate can file a lien. You hire a contractor W to do work, he buys material from X and has Y do the work. W, X and Y can each file liens, to the extent there is a valid claim for compensation.

A lien is only as good as the proof of the claim it purports to secure.

On the other hand, if you object to the expenses of the executor, you can petition the probate court to disallow any part of the estate accounting that is questionable, and let her prove it was justified.

I know this phrase is sometimes over used, but retain legal counsel right away on this: Why was the work order? Was it needed to preserve the house from further damage? Or are we talking cosmetic? If cosmetic then it sounds like she may have violated her fiduciary duty to the other heirs? Check state law but most likely the contractor had to be licensed, another avenue would be check to see if permits where required? If so my bet they where not pulled based upon unlicensed contractors, check with local building codes that maybe another avenue, could be negligence on her part if no permits, and licensed contractors where required

She would have to have a contract or some type of proof that she did work on the house and was not compensated for it to take a contractors/ mechanics lien. Or you can protest the will and hold up the selling of the house and disbursement of any assests if you think there is something fishy going on.