swim against the tide

we read lyman and henry story in class today. i think henry just like to swim. i dont think he has psychological problem at that moment. after the fight between the brothers,old henry is actually back. Henry just want to show off or something like that,more like swim against the tide. but he failed. and i dont think he died. i think his head hit the rock or something and he lost the memorise, so he couldnt find the way to back home. that is what i thought,maybe its not ture,who knows!