It is stated early in the film that Buddy is 13 years old, yet on his missing sign, it says he is only 10.
George jumps into a pool to save a young boy from drowning. He swims very well. George has a condition from birth which makes it extremely dangerous for him to allow his head to get wet. He almost died once after being baptized in water. With this condition, it is highly unlikely for him to have learned to swim as well as he does.