sloane,
What you have somewhat is a defacto custodial arrangement. You are looking and caring after the child with the CAS endorsement. This defacto arrangement looks good on you for a future application for custody of the child. For these reasons,
a) it appears the parents have abandoned the child and have left the child in your care.
b) CAS is involved and is aware of the situation and basically supporting the child in your care.
The longer this arrangement goes on, the less likely the courts would interrupt a status quo arrangement if you are able and willing to look after the child.
For the legal side of it, you could bring forth an application under the Children's Law Reform Act.
Section 21
Application for custody or access
21. A parent of a child
or any other person may apply to a court for an order respecting custody of or access to the child or determining any aspect of the incidents of custody of the child. R.S.O. 1990, c. C.12, s. 21.
The Application form that you would have to fill out is Form 8 - Application (general) which can be found here.
http://www.ontariocourtforms.on.ca/e...mily/index.jsp
In your application, you would have to name BOTH parent's as Respondent's in the matter and serve both of them. Reason being is that at law at the present time the two parents are equally entitled to share the responsibilities and the benefits of custody. In other words, at law they in fact each have coextensive custody of the child at the present time. It appears somewhat though that they have abandoned this responsibility to look after the child.
Your claim is not frivolous or vexatious
lv