re: Question about pouring concrete

Without seeing the plasticity of the clay in person hard to tell. I wouldn't be to concerned with pouring directly on the soil for the patio as it is not subject to heavy loads. But for your driveway I'd seriously consider excavating out 4-6" of the clay and installing a basecourse (crushed concrete, CR610, #57 Stone, etc.). It'll add some cost but best to do this only one time. How thick is he planning to pour the driveway? This will create a "drainage layer" so to speak to allow any water that percs through the concrete to disperse instead of being directly absorbed by the clay and potentially causing some settlement.