Fit to work document

My wife was diagnosed with severe depression and she is undergoing treatment, meaning we have to go evry 2 weeks to PGH for her session, she can still work though sometimes depression strikes her. last week she was absent for 3 days because of that. and now her employer sutherland is asking her to submit a fit to work document or else they wont accept her. we already ask her psychiatrist and was told it will only be given once she is completely ok. depression is a disorder not a sickness. documents has been provided that clearly shows that she has depression. what can we do about this? Thanks in advance

Most likely that means your wife will have to be on leave of absence in the meantime.

It also seems the doctor believes your wife should not be reporting to work until the completion of the "treatment."