can you swim?

I always thought that everyone can swim...my kids are natural....Katie is our mermaid...never had a swimming lesson ...but started dunking her head in the bathtub... when she was just 18 months...by 2 she could swim in the shallow end of our pool and by 3 she was swimming laps in the deep end...she even swims to the bottom our 8 foot deep pool, is working on her dive and can do handstands and somersaults.......my other 2 kids were the same...so today when we were at the water park in Niagara...I just assumed that my dad could swim in 4 feet of water....he took Jamie down one of the water slides but at the end of the ride...the tube flipped.....as I was taking pictures I suddenly realized that my dad couldn't find his feet to stand....he kept dunking his head in the water.....fortunately at that point the lifeguard jumped into the pool to help him....everything happened so fast....Jamie got out of the water with that look on his face...like "what" ...as my dad staggered out of the pool looking like a drowned rat....can't you swim I asked?..." no"....oh guess I didn't know that about him......and that was that....he dried off and we carried on with our day....nothing more said........so tonight as I am bloggin I am thinking....jeez he could have drown today.......and that young lifeguard actually helped saved a life today.....things could have turned out so different...so next time you take someone to a water park...maybe ask them if they can swim??!! because as they say "assume"....only means making an ass of u and me....