Yucca plants dying?help please

virginall

Hi 
a couple of months ago a friend looked after my yucca and overwatered it as all the leaves turned yellow. I left it by the window where there is a lot of sunlight and let it dry but now It looks like it’s still dying (see pictures). Do I need to re-pot it? How can I save it?
thanks for your help
virginie 

Buttercupdays

Is it in another pot inside the ceramic one?

If there is nowhere for the water to drain, then the roots may have begun to rot and putting it in the sun will have added more stress. It needs decent compost (J.I.no 2 or 3) lightened with a little MPC and some grit or perlite added for drainage, in a pot with drainage holes, slightly raised, so  surplus water can escape. I would check the roots and remove any rotten bits if you see some, and then repot it and keep it somewhere fairly shaded until it has had some time to recover. Check the water level in the ceramic / outer pot from time to time to make sure it is not too high.

Good luck