Catering services and additional business with that

One of my client is doing outdoor catering services. He is collecting 5% GST and for that without claiming any input tax I am filing his gst returns by discharging 5% GST under regular basis (not a composition dealer). But now in addition to that he want to sale a seperate product which is taxable at 18% which is not belongs to catering. Now can he claim input tax relating to that products seperately.