I think Jonas is dead because as he keeps going on the landscape changes in to something more natural and the world changes into the world before sameness, which was the world Jonas wanted to live in. this could mean he is already dead and his soul is living the life he wanted to live because the giver said the whole world chose to go into sameness which means there couldn’t have heard people singing or seen houses with Christmas lights and trees as if the whole world chose to go into sameness there wouldn’t be people who still have memories of things like love and colors. Also because the whole world chose to go into sameness the sled at the top of the hill would have been frozen and coved in snow and the rope would have been rotting and falling apart