Hello netcoaching,
If the claimants condition has deteriorated since their original claim then an appeal would not be appropriate. They can contact the DWP to report a deterioration. They would be reassessed and they would need to provide compelling medical evidence to support their deterioration. There is always the risk that they could be awarded a reduced award or even no award at all. They will need to think very carefully before deciding to report the change.
Nothing on this board constitutes legal advice - always consult a professional about specific problems