If you are unable to carry out your role because of illness, then they within their rights to make you redundant/sack you. Any decent employer would try and make resonable adjustments (ie maybe change your role a bit to avoid the things that stress you). The fact that they are coming to you means they are thinking of you, rather than making you come into work for the meeting. I would imagine you would have a right to have a representative attend (union?)
basically you should either have a policy/procedure or and employee handbook outlining the procedure.
As i said, if you are unable to carry out that role for which they pay you, they can cease to employ you