Hi, XXXXXXXXX, it looks like your employee is completely normal, if the doctors have performed so many tests , with negative results, he is suffering ,what doctors call hypochondria.
and the best measure for him, will be to consult a psychiatrist.
The treatment will include psychotherapy with certain drugs ,specially a selective serotonin reuptake inhibitor and tricyclic antidepressant , these drugs will decrease his anxiety ,disease fear and the false perception, that he is experiencing all these symptoms.
He need to consult a psychiatrist specialist, they are able to manage ,this kind of problem.
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Doctor (MD)
MD