You said that God the Father judged the Son on the Cross. Your example (John 5) doesn' say antyhing about God the Father judging the Son. Judge Him for what?
For the imputed sins of all mankind, past, present, and future. Now that they have been judged by Perfect Justice, His Perfect Righteousness is free to grace us with forgiveness upon recognizing our faith alone in Christ alone, which He provides for us, for that faith is the same as that of the Son which was found to be righteous.