WordPress credentials not Passing

Hey fellow Devs,

I have officially broken my keyboard and my monitor is almost out the window, so i would be appreciated if someone could help me.

I am attempting to create a WordPress SSO for a custom Login System. When a user logs on to the WordPress Website ( or changes the password or the email) it will fire up the SSO functions after the user has been validated by WordPress.

The problem here is that its not passing any values to the fireCustomLoginFunction found below. What did I do wrong?

Here is a sample code:

function custom_login() {
//## Function used to 'Auto' Login to Custom if user is accepted from WordPress.

    //## Check if user is signed on.
    if ( !is_user_logged_in() ) {

       //## User is Not Logged in, return 'false'
       return;

    }

    //## Assign Varibles (is this too risky?)
    //## Not sure if the $_POST['value'] will be the best way for this.
    $NewUserCred_username  = $_POST['log'];
    $NewUserCred_password  = $_POST['pwd'];

    //## Fire up Custom Validation.
    //## Will set Custom Session if Successful.
    fireCustomLoginFunction($NewUserCred_username, $NewUserCred_password);

}

//## Maybe should run this during wp_signon or wp_login?
add_action( 'after_setup_theme', 'custom_login', 100 );

I can truly use some help on this. The fireCustomLoginFunction needs to use the NON Hashed version of the password to log the user into the Custom system, but the user must be validated by wordpress prior to being accepted by the custom function.