Iron clad immune system

I am convinced my 3 year old nephew has the worlds greatest immune system.  One day we were relaxing in the pool house.  It rained the day before so things were still pretty damp all around the patio area.  My sister and I just happened to come out of the pool house in time to see my nephew hoist himself up on his tip toes and in one long disgusting slurp suck all the water that accumulated in the handle of the garbage can! EEWWW!  On another occasion, my sister was washing her SUV while 3 of my nephews played in the yard.  One of them called me to watch how high he can climb one of the trees.  As I walked down the driveway, past my sisters SUV I saw the 3 year old laying on his back with his mouth wide open just like a little baby bird catching the water as it fell from the vehicle and even better the tailpipe.  BLUK!  So yeah, if this kid ever gets sick, it will be news to me!