Well you wife is not supposed to work as long as she is under your sponsorship and has entered Qatar on a family visit visa. Visit visa is for visiting/meeting family or friends and its sure not for work. If she starts working under visit visa & gets caught by Labor ministry inspectors or CID, then they can impound fines on you or may even deport both of you out of Qatar. If she really wants to work, then she has to get a company sponsorship & get proper work visa & designation to work in her field. I suggest don't risk your wife to work under visit visa.