I am sure she is incapacitated by her symptoms, but they are secondary to her beliefs. Exposure to EM radiation does not cause them; lack of exposure is not helpful in reducing them. Therefore she shouldn't receive "disability" payments (as she is handicapped, not disabled - she is fully able but doesn't believe it); she should be encouraged towards a model of the world which allows her to participate in society (assuming that she lives in a society which helps those worse off - not being in Britain must be an advantage). This would likely be careful repeated proof that she is not affected by EM radiation, explained by someone nice in a non-judgemental way.
A previous boss managed to convince a patient that they didn't have the problem they thought they did through a double-blind exposure trial. It had an awesome effect - they are happily living their life without bothering doctors; doctors are not becoming disgruntled about wasting time on such nonsense; they can take the meds they thought they couldn't. Abrupt confrontation sadly just reinforces beliefs; you can't change people's mind by shouting at them no matter how right you are (see: Richard Dawkins, homoeopathy, astrology, etc etc)