@ angelbrat..
they are over 22 already..one 23 and the other 24..both of them are dependent though coz they dont really technically work yet. :|
Your original post is not really clear but I will answer what I think based on the information provided.
It sounds to me like your friend's parents applied for immigration to Canada and included your friend and her sister in the application. So my question is were they YOUNGER than 22 when the application was initially SUBMITTED? If the answer is YES, then their age was "locked in" at the time of submission and even though they are not studying now, it should not have a negative impact on their inclusion as dependents as long as they have not gotten married or entered into a common-law relationship.