I will dive in with a recommendation but I come at this without any professional experience in this type of work, just a hard core DIYer. I see you are asking about replacing the skimmer in another post. I would worry about that first. After that is done, I would drill down along both edges of your broken coping, a few inches in and every few inches along the edges. I would cut rebar to fit in these hole and epoxy them in. Then I would wire rebar along the uprights. I would clean the exposed concrete, build a form that matches the original form of the pool, put down an adhesion agent, and fill the area it with some high quality cement that is used for patching to existing concrete. Not sure of what brand I would use but I have seen it at the box shops.