Estate issues

What happens when a parent made a Will that stated his children were co executrix of the estate and allows his widow to live in the house until she marries, dies, or cohabitates, doesn't pay the taxes, or keep up with the maintenance of the house? The Will also states that the children can take all small things from the premises only to leave her a bed, couch, dining room table and other big objects. Is there any legal right to the estate (the children) when the widow switched the locks on them using the decedent's credit card and not being an authorized user? Does the estate have a legal right to have a key to the house being that the deed remains in the decedent's name and also, what if a fire were to happen? Who does the property legally belong to even though she's permitted to live there under certain conditions? Please help.

She gets full use and access to the house and controls it until she dies normally.

...she does have to do the reasonable and customary maintenance unless some other provision addresses that.

What is actually going on there?