How to find usage of each object in other objects from a database?

I am with the task of taking an old **SQL Server database** and identify all of it's objects and their relationships, because the one who made it did not bother to use any foreign key, he just made all *relations* inside the code. So my mission is to identify usages, relationships and make a graphic model, which I think I will use ERwin7 to do it. I stated today taking every table name and searching it in the source-code and sql metadata. I open all those files in separated instances of Notepad++ and search to see if anyone really uses that table in the source-code or in any stored procedure or function. But there are 1500+ c# files and 857 objects in the database. - Is there a better way to do that? - Is there a tool to tell me where each table is used in the code and in the database without the need of Ctrl+F for each table name or other objects I will also check? - Is ER-win a reasonable choice for doing the re-modeling?