Uncooperative Joint Executor

Newly_retired

I can't see the point in that suggestion and at least two disadvantages as stated.

thegreenone

Perhaps offer Uncooperative Sibling the chance to buy it.  If she can't/won't, it needs to go on the market asap to stop the bills building up and the estate reducing.  

As difficult as this would be, perhaps consider changing the locks and giving the EA the new keys.  As hard as this may be, this is a business transaction now and US has to stop using the flat as her holiday home and potentially blocking a sale.