I can suggest three things...
1: if he goes to the future, after a while he discover that he can't go back in time, and remains trapped in that dimension...
2: if he goes back in time, he changes a historic event, which makes the inventor of the time machine "never born", so he go back to the present (original, uh?), forgetting everything he saw, because he never could have done the time travel...
3: he discover that the time machine is instead a "dimension traveler machine", and flies from a dimension to another, trying to go back in his dimension...at the end he discover that the "machine" never comes back to the same dimension, and he goes on travelling searching a good place to live...which he will never find...
sad endings...