Overheating problem

I have a friend that has an Astro and recently he said the van has been overheating and apparently yesterday he noticed antifreeze on the garage floor... he thought it seemed to be coming from near the radiator cap... cap was on tight and overflow tube was still connected... I have not seen this myself.... Could this be a Thermostat problem causing the overheating and an old (bad) radiator cap not holding the pressure?

it certainly could be the thermostat. If the thermostat is old it may be rusted and crudded up. if it's frozen closed the engine will over heat.
if there is evidence of a leak in the vicinity of the radiator cap, check the overflow hose to the resevoir

What year is the van? He should physically take the radiator cap and look inside. If it empty he should look for a leaky radiator, intake gasket, waterpump, lines. It might be a dexcool van and be sludged up.

Water Pump was Problem....