He feels awful but its not his fault?

i live with my godfather, Kai, and his niece and nephew who were orphaned after their father was killed in action over seas. i live with him for summers while my parents go do their thing in the peace corps with my sisters. Kai doesnt mind this, but he feels bad that often times im stuck at home with the kids while he goes to earn a living. it sucks, but i dont mind all that much. but he does. he feels awful, but he shouldnt. what can i do to convince him that im fine? please help