I have never seen a maximum age for a child to have a live-in caregiver. A child becomes an adult in Canada at age 18. Now, I suppose it is not common to have a live-in caregiver for a 15 yo. but they might have a good reason for it, maybe they work nights and don't want the 15 yo. to be alone in the house in case the 20 yo. sibling is not home.
ARE THOSE KINDS OF REASONS ACCEPTABLE?? CAUSE BOTH THE PARENTS ARE WORKING FULLTIME AND THE 20 YR OLD GOES TO UNIVERSITY DOWNTOWN HE'S JUST HOME DURING THE WEEKENDS AND SCHOOL BREAKS.