Giving child custody without the court
My ex-husband had full custody of our son (child support waived). My ex passed away in June. My son has always lived in the Dallas area with his dad, stepmom, and his dad's family. My son wants to stay in Dallas and the family wants him to stay. I want to give his grandparents custody of him. Mainly because he is a teenager that has a tendency to get into trouble and I do not agree with the relaxed view of disipline the family in Dallas has. If he was under my supervision, the reins would be a lot tighter! So when he gets into trouble or arrested or takes on debt or gets into a car accident (since they are allowing him to get a car), I do not want to be left "holding the bag". I believe if he is under their care they need to be the ones to "bail him out".
How do I go about giving the grandparents full custody/guardianship without having to go through the whole court system? Is there an agreement that can be drawn up, then signed by both parties, and then maybe notorized?