What about the in/out flows of this account? Did the money appear suddenly in account?
For study permit you need 1 year fees + 10,000 + a bit more for travel and such. And you need to explain how the other years amount will be obtained.
So while technically it was enough the fact that this is your relative and not immediate family member is probably raising doubts, how likely is it that a relative is going to give up all of their funds for you to study? I would recommend getting the caups notes for better clarity before applying.