What does having ‘reasonably’ physical and mental health really mean?

You are considered to be physically stable if your underlying medical conditions are being treated and are considered under control. For instance, if you have diabetes, your diabetes is under control.

You are considered to be mentally stable when your underlying conditions, if you have any, are being treated and you are able to make decisions regarding your future. For instance, if you have depression and/or anxiety, these conditions are being treated and you feel stable enough to make life-altering decisions regarding your healthcare.