What should I get him for a gift?

Well, I was swimming in a lake and let's just say something happened and i almost drowned. This man I had only met that day and didn't speak much too, jumped in and saved me. He had to do CPR and all that stuff. :/ I kind of know where he lives ( i asked around) and I wanted to give him a present. i know nothing can be given in return that would equal anywhere near my life, but I need to give him something.I can't even fathom what it should be... does anyone have some ideas?