If they have done any research into it or have a halfway decent agent, yes. A book that sells well is probably not going to set you up for life and at best will

If they have done any research into it or have a halfway decent agent, yes. A book that sells well is probably not going to set you up for life and at best will just cover the next year or two, only a tiny minority of writers get that massive best seller and movie deal that sets them up for life.