It was a story I read around 10ish years ago though I think the book may have been older than that. It was about a boy who ends up on a ship and is somehow cursed to live forever. He then washes up onshore with his dog and goes around helping people with guidance from an Angel telling him where to go next. I believe he could also talk to his dog but no one else could.
I believe it starts around the 1500/1600s and then moves into the future as they move around places.
If I remember correctly they started out helping a shepherd and then it moves on to them helping some old woman. Here they befriend some young people and help them out as well.
I think it ends with them leaving as a bell goes off.